View source for Python (programming language)

{{Short description|General-purpose programming language}}
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{{Cleanup list|date=October 2025}}
{{Use dmy dates|date=November 2021}}
{{Use American English|date=December 2024}}
{{Infobox programming language
| logo = Python-logo-notext.svg
| logo size = 150px
| paradigm = [[Multi-paradigm]]: [[Object-oriented programming|object-oriented]],<ref>{{Cite web |title=General Python FAQ – Python 3 documentation |url=https://docs.python.org/3/faq/general.html#what-is-python |access-date=7 July 2024 |website=docs.python.org}}</ref> [[Procedural programming|procedural]] ([[Imperative programming|imperative]]), [[Functional programming|functional]], [[Structured programming|structured]], [[Reflective programming|reflective]]
| released = {{start date and age|1991|02|20|df=y}}<ref name="alt-sources-history">{{cite web |title=Python 0.9.1 part 01/21 |url=https://www.tuhs.org/Usenet/alt.sources/1991-February/001749.html |url-status=live |archive-url=https://web.archive.org/web/20210811171015/https://www.tuhs.org/Usenet/alt.sources/1991-February/001749.html |archive-date=11 August 2021 |access-date=11 August 2021 |publisher=alt.sources archives}}</ref>
| designer = [[Guido van Rossum]]
| developer = [[Python Software Foundation]]
| latest release version = {{wikidata|property|edit|reference|P548=Q2804309|P348}}
| latest release date = {{start date and age|{{wikidata|qualifier|single|P548=Q2804309|P348|P577}}}}
| latest preview version = <!-- 3.15.0a1 on 15 October 2025 {{wikidata|property|edit|reference|P548=Q51930650|P348}} doesn't work, nor what AI suggested as fix: {{#invoke:Wikidata | claim | P348 | qualifier = P548:Q51930650 | rank = best }} -->
| latest preview date = {{start date and age|2025|08|18|df=y}} <!-- {{start date and age|{{wikidata|qualifier|Q28865 |P548=Q51930650|P348|P577}}}} nor
{{#invoke:Wikidata | qualifier | P348 | P577 | qualifier = P548:Q51930650 | rank = best | formatting = date }}
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| typing = [[Duck typing|Duck]], [[Dynamic typing|dynamic]], [[Strong and weak typing|strong]];<ref>{{Cite web |title=Why is Python a dynamic language and also a strongly typed language |url=https://wiki.python.org/moin/Why%20is%20Python%20a%20dynamic%20language%20and%20also%20a%20strongly%20typed%20language |url-status=live |archive-url=https://web.archive.org/web/20210314173706/https://wiki.python.org/moin/Why%20is%20Python%20a%20dynamic%20language%20and%20also%20a%20strongly%20typed%20language |archive-date=14 March 2021 |access-date=27 January 2021 |website=Python Wiki}}</ref> [[Optional typing|optional type annotations]]{{efn|since 3.5, but those hints are ignored, except with unofficial tools<ref name="type_hint-PEP">{{cite web |last1=van Rossum |first1=Guido |last2=Levkivskyi |first2=Ivan |title=PEP 483 – The Theory of Type Hints |url=https://www.python.org/dev/peps/pep-0483/ |url-status=live |archive-url=https://web.archive.org/web/20200614153558/https://www.python.org/dev/peps/pep-0483/ |archive-date=14 June 2020 |access-date=14 June 2018 |website=Python Enhancement Proposals (PEPs)}}</ref>}}
| memory management = [[Garbage collection (computer science)|Garbage-collected]]
| implementations = [[CPython]], [[PyPy]], [[MicroPython]], [[CircuitPython]], [[IronPython]], [[Jython]], [[Stackless Python]]
| operating system = [[Cross-platform]] including 32-bit [[Windows&nbsp;10]]<!-- with latest Python 3.14, Win8.1 still supported with older --> and e.g. for mobile; [[Android (operating system)|Android]] and [[iOS]] <small>(both 64-bit)</small><!-- downloadable official Python 3.14 Android binary executable available; still only tier 3 support. Strangely I find only Android, no iOS, official executable download despite it has "arm64-apple-ios" tier 3 support, so only downloadable as source code; and as unofficial iOS/iPadOS download?! -->{{efn|
* '''Tier 1''': 64-bit [[Linux]], [[macOS]]; 64- and 32-bit [[Windows&nbsp;8.1]] and later with older Python versions<!-- Windows 8.1 supported with 3.10 to 3.13 but only Windows 10+ with latest Python 3.14+--><ref>{{Cite web |last1=von Löwis |first1=Martin |last2=Cannon |first2=Brett |title=PEP 11 – CPython platform support |url=https://peps.python.org/pep-0011/ |access-date=22 April 2024 |website=Python Enhancement Proposals (PEPs) |language=en}}</ref><!--Not "Windows for IoT and embedded systems"; NOT UNIX, it's not listed, nor any Unix-like, maybe implied Possibly Windows 8.1 is also supported on at least Python 3.9? Might also work on latest, seems too minor to mention, for any Python version. Windows 7 and 8 are prevented to work on Python 3.9, though it might not rule out 8.1, also some info like this might be a bit wrong:

"Windows 8 and newer for Python 3.9
FreeBSD 10 and newer
macOS Snow Leopard (macOS 10.6, 2008) and newer"
-->
* '''Tier 2''': E.g. 32-bit [[WebAssembly]] (WASI) <!-- (WASI SDK, Wasmtime) meaning wasm32-unknown-wasi; wasm32-unknown-emscripten is unsupported since 3.13. aarch64-pc-windows-msvc and powerpc64le-unknown-linux-gnu -->
* '''Tier 3''': 64-bit [[Android (operating system)|Android]]<!-- too much trivia to mention "5.0+", even if true, it seemingly is, and corresponding API levels, but thouse are ancient, possibly even only way more recent is officially supported? -->,<ref>{{Cite web |title=PEP 738 – Adding Android as a supported platform {{!}} peps.python.org |url=https://peps.python.org/pep-0738/ |access-date=19 May 2024 |website=Python Enhancement Proposals (PEPs) |language=en}}</ref> [[iOS]], [[FreeBSD]], and (32-bit) [[Raspberry Pi OS]]<br />Unofficial (or has been known to work): Other [[Unix-like]]/[[BSD]] variants) and a few other platforms<!-- Used to support many more, only few support latest 3.9+ --><ref name="DownloadOther">{{Cite web |title=Download Python for Other Platforms |url=https://www.python.org/download/other/ |url-status=live |archive-url=https://web.archive.org/web/20201127015815/https://www.python.org/download/other/ |archive-date=27 November 2020 |access-date=18 August 2023 |website=Python.org |language=en}}</ref><ref>{{Cite web |title=test – Regression tests package for Python |url=https://docs.python.org/3.7/library/test.html?highlight=android#test.support.is_android |url-status=live |archive-url=https://web.archive.org/web/20220517151240/https://docs.python.org/3.7/library/test.html?highlight=android#test.support.is_android |archive-date=17 May 2022 |access-date=17 May 2022 |website=Python 3.7.17 documentation}}</ref><ref>{{Cite web |title=platform – Access to underlying platform's identifying data |url=https://docs.python.org/3.10/library/platform.html?highlight=android |url-status=live |archive-url=https://web.archive.org/web/20220517150826/https://docs.python.org/3/library/platform.html?highlight=android |archive-date=17 May 2022 |access-date=17 May 2022 |website=Python 3.10.4 documentation}}</ref>}}

<!--
https://mail.python.org/archives/list/python-committers@python.org/thread/K757345KX6W5ZLTWYBUXOXQTJJTL7GW5/
* Alpine / musl is not supported, because our test suite is failing due to bugs and missing features in musl libc.
* NetBSD and OpenBSD are in a similar state as Alpine: no stable buildbot and AFAIK tests are failing
* [outdated]
* Cygwin and MinGW are officially unsupported, see bpo-45537 and bpo-45538

..

The policy Brett is proposing just makes that explicit and gives us something to point to when someone comes up with a patch to support PDP-11 or when someone's patch for Android breaks Windows.  I don't think we'll wind up with tier support police; if a core dev wants to take responsibility for a patch for a platform that is not tier 3 or above they can still do that, but if it breaks things for a supported platform it will be reverted.

..

E.g. Android support was even funded by the PSF recently.[outdated]
Also, note that the stdlib does in fact support other Python implementations reusing (parts of) it, e.g. Jython, PyPy and IronPython. Again, without core devs backing these.
-->| license = [[Python Software Foundation License]]
| file ext = .py, .pyw, .pyz,<!-- Too much trivia?: (since 3.5), since 3.8 latest supported and Python 3.5.10 Sept. 5, 2020--><ref>{{cite web |last1=Holth |first1=Daniel |last2=Moore |first2=Paul |date=30 March 2014 |title=PEP 0441 – Improving Python ZIP Application Support |url=https://www.python.org/dev/peps/pep-0441/ |url-status=live |archive-url=https://web.archive.org/web/20181226141117/https://www.python.org/dev/peps/pep-0441/%20 |archive-date=26 December 2018 |access-date=12 November 2015 |website=Python Enhancement Proposals (PEPs)}}</ref><br />
.pyi, .pyc, .pyd<!-- too much trivia: .pyo (before 3.5)<ref>File extension .pyo was removed in Python 3.5. See [https://www.python.org/dev/peps/pep-0488/ PEP 0488] {{Webarchive|url=https://web.archive.org/web/20200601133202/https://www.python.org/dev/peps/pep-0488/ |date=1 June 2020}}</ref> -->
| website = {{URL|https://www.python.org/|python.org}}
| dialects = [[Cython]], [[RPython]], [[Starlark]]<ref>{{cite web |title=Starlark Language |url=https://docs.bazel.build/versions/master/skylark/language.html |url-status=live |archive-url=https://web.archive.org/web/20200615140534/https://docs.bazel.build/versions/master/skylark/language.html |archive-date=15 June 2020 |access-date=25 May 2019 |website=bazel.build}}</ref>
| influenced by = [[ABC (programming language)|ABC]],<ref name="faq-created" /> [[Ada (programming language)|Ada]],<ref>{{cite web |title=Ada 83 Reference Manual (raise statement) |url=https://archive.adaic.com/standards/83lrm/html/lrm-11-03.html#11.3 |url-status=live |archive-url=https://web.archive.org/web/20191022155758/http://archive.adaic.com/standards/83lrm/html/lrm-11-03.html#11.3 |archive-date=22 October 2019 |access-date=7 January 2020 |website=archive.adaic.com}}</ref>{{failed verification|date=August 2025|reason=The source does not talk about Python. The "raise" keyword it describes is very similar to the Python version, but this is original research (see WP:OR).}} {{nowrap|[[ALGOL 68]]}},<ref name="98-interview" /> [[APL (programming language)|APL]],<ref name="python.org">{{cite web |title=itertools – Functions creating iterators for efficient looping |url=https://docs.python.org/3.7/library/itertools.html |url-status=live |archive-url=https://web.archive.org/web/20200614153629/https://docs.python.org/3/library/itertools.html |archive-date=14 June 2020 |access-date=22 November 2016 |website=Python 3.7.17 documentation |quote=This module implements a number of iterator building blocks inspired by constructs from APL, Haskell, and SML.}}</ref> [[C (programming language)|C]],<ref name="AutoNT-1" /> [[C++]],<ref name="classmix" /> [[CLU (programming language)|CLU]],<ref name="effbot-call-by-object" /> [[Dylan (programming language)|Dylan]],<ref name="AutoNT-2" /> [[Haskell]],<ref name="AutoNT-3" /><ref name="python.org" /> [[Icon (programming language)|Icon]],<ref name="AutoNT-4" /> [[Lisp (programming language)|Lisp]],<ref name="AutoNT-6" /> {{nowrap|[[Modula-3]]}},{{r |98-interview}}<ref name="classmix" /> [[Perl]],<ref>{{cite web |title=re – Regular expression operations |url=https://docs.python.org/3.10/library/re.html |url-status=live |archive-url=https://web.archive.org/web/20180718132241/https://docs.python.org/3/library/re.html |archive-date=18 July 2018 |access-date=6 September 2022 |website=Python 3.10.6 documentation |quote=This module provides regular expression matching operations similar to those found in Perl.}}</ref> [[Standard ML]]<ref name="python.org" />
| influenced = [[Apache Groovy]], [[Boo (programming language)|Boo]], [[Cobra (programming language)|Cobra]], [[CoffeeScript]],<ref>{{Cite web |title=CoffeeScript |url=https://coffeescript.org/ |url-status=live |archive-url=https://web.archive.org/web/20200612100004/http://coffeescript.org/ |archive-date=12 June 2020 |access-date=3 July 2018 |website=coffeescript.org}}</ref> [[D (programming language)|D]], [[F Sharp (programming language)|F#]], [[GDScript]], [[Go (programming language)|Go]], [[JavaScript]],<ref>{{cite web |last=Rauschmayer |first=Axel |date=24 February 2013 |title=Perl and Python influences in JavaScript |url=https://www.2ality.com/2013/02/javascript-influences.html |url-status=live |archive-url=https://web.archive.org/web/20181226141121/http://2ality.com/2013/02/javascript-influences.html%0A |archive-date=26 December 2018 |access-date=15 May 2015 |website=2ality.com}}</ref><ref>{{cite web |last=Rauschmayer |first=Axel |title=Chapter 3: The Nature of JavaScript; Influences |url=https://speakingjs.com/es5/ch03.html |url-status=live |archive-url=https://web.archive.org/web/20181226141123/http://speakingjs.com/es5/ch03.html%0A |archive-date=26 December 2018 |access-date=15 May 2015 |website=Speaking JavaScript |publisher=O'Reilly}}</ref> [[Julia (programming language)|Julia]],<ref name="Julia">{{cite web |last1=Bezanson |first1=Jeff |last2=Karpinski |first2=Stefan |last3=Shah |first3=Viral B. |last4=Edelman |first4=Alan |date=February 2012 |title=Why We Created Julia |url=https://julialang.org/blog/2012/02/why-we-created-julia |url-status=live |archive-url=https://web.archive.org/web/20200502144010/https://julialang.org/blog/2012/02/why-we-created-julia/ |archive-date=2 May 2020 |access-date=5 June 2014 |website=Julia website |quote=We want something as usable for general programming as Python [...]}}</ref> [[Mojo (programming language)|Mojo]],<ref name="Mojo">{{Cite web |last=Krill |first=Paul |date=4 May 2023 |title=Mojo language marries Python and MLIR for AI development |url=https://www.infoworld.com/article/3695588/mojo-language-marries-python-and-mlir-for-ai-development.html |url-status=live |archive-url=https://web.archive.org/web/20230505064554/https://www.infoworld.com/article/3695588/mojo-language-marries-python-and-mlir-for-ai-development.html |archive-date=5 May 2023 |access-date=5 May 2023 |website=InfoWorld |language=en}}</ref> [[Nim (programming language)|Nim]], [[Ring (programming language)|Ring]],<ref name="The Ring programming language and other languages">{{cite web |author=Ring Team |date=4 December 2017 |title=Ring and other languages |url=https://ring-lang.sourceforge.net/doc1.6/introduction.html#ring-and-other-languages |url-status=dead |archive-url=https://web.archive.org/web/20181225175312/http://ring-lang.sourceforge.net/doc1.6/introduction.html#ring-and-other-languages |archive-date=25 December 2018 |access-date=4 December 2017 |work=ring-lang.net |publisher=[[ring-lang]]}}</ref> [[Ruby (programming language)|Ruby]],<ref name="bini" /> [[Swift (programming language)|Swift]],<ref name="lattner2014">{{Cite web |last=Lattner |first=Chris |date=3 June 2014 |title=Chris Lattner's Homepage |url=http://nondot.org/sabre/ |url-status=live |archive-url=https://web.archive.org/web/20181225175312/http://nondot.org/sabre/ |archive-date=25 December 2018 |access-date=3 June 2014 |publisher=Chris Lattner |quote=The Swift language is the product of tireless effort from a team of language experts, documentation gurus, compiler optimization ninjas, and an incredibly important internal dogfooding group who provided feedback to help refine and battle-test ideas. Of course, it also greatly benefited from the experiences hard-won by many other languages in the field, drawing ideas from Objective-C, Rust, Haskell, Ruby, Python, C#, CLU, and far too many others to list.}}</ref> [[V (programming language)|V]]<ref name="vpeople">{{Cite web |title=V documentation (Introduction) |url=https://github.com/vlang/v/blob/master/doc/docs.md#introduction |access-date=24 December 2024 |website=GitHub |language=en}}</ref>
<!-- Do not put in as there's a pure Java implementation (Jython): | programming language = [[C (programming language)|C]] -->| wikibooks = Python Programming
}}
{{Python sidebar}}

'''Python''' is a [[high-level programming language|high-level]], [[general-purpose programming language]]. Its design philosophy emphasizes [[code readability]] with the use of [[significant indentation]].<ref name="AutoNT-7" /> Python is [[type system#DYNAMIC|dynamically type-checked]] and [[garbage collection (computer science)|garbage-collected]]. It supports multiple [[programming paradigm]]s, including [[structured programming|structured]] (particularly [[procedural programming|procedural]]), [[Object-oriented programming|object-oriented]] and [[functional programming]].

[[Guido van Rossum]] began working on Python in the late 1980s as a successor to the [[ABC (programming language)|ABC]] programming language. Python&nbsp;3.0, released in 2008, was a major revision and not completely [[backward-compatible]] with earlier versions. Beginning with Python 3.5,<ref>{{cite web |title=PEP 484 – Type Hints |url=https://peps.python.org/pep-0484/ |website=Python Enhancement Proposals |access-date=27 October 2025 |language=en}}</ref> capabilities and keywords for typing were added to the language, allowing optional [[static typing]].<ref>{{Cite web |title=mypy – Optional Static Typing for Python |url=https://mypy-lang.org/ |access-date=17 August 2025 |website=mypy-lang.org}}</ref> {{As of|2025}}, the Python Software Foundation supports Python 3.10, 3.11, 3.12, 3.13, and 3.14, following the projects annual release cycle and five-year support policy. Earlier versions in the 3.x series have reached end-of-life and no longer receive security updates. 

Python has gained widespread use in the [[machine learning]] community.<ref>{{Cite web |title=Stack Overflow Developer Survey 2022 |url=https://survey.stackoverflow.co/2022/ |url-status=live |archive-url=https://web.archive.org/web/20220627175307/https://survey.stackoverflow.co/2022/ |archive-date=27 June 2022 |access-date=12 August 2022 |website=Stack Overflow |language=en}}</ref><ref>{{Cite web |title=The State of Developer Ecosystem in 2020 Infographic |url=https://www.jetbrains.com/lp/devecosystem-2020/ |url-status=live |archive-url=https://web.archive.org/web/20210301062411/https://www.jetbrains.com/lp/devecosystem-2020/ |archive-date=1 March 2021 |access-date=5 March 2021 |website=JetBrains |language=en}}</ref><ref name="tiobecurrent">{{cite web |title=TIOBE Index |url=https://www.tiobe.com/tiobe-index/ |url-status=live |archive-url=https://web.archive.org/web/20180225101948/https://www.tiobe.com/tiobe-index/ |archive-date=25 February 2018 |access-date=3 January 2023 |publisher=TIOBE |quote=The TIOBE Programming Community index is an indicator of the popularity of programming languages}} Updated as required.</ref><ref>{{Cite journal |last1=Healy |first1=John |last2=McInnes |first2=Leland |last3=Weir |first3=Colin |date=2017 |title=Bridging the Cyber-Analysis Gap: The Democratization of Data Science |journal=The Cyber Defense Review |volume=2 |issue=1 |pages=109–118 |issn=2474-2120 |jstor=26267404 |quote="Python is the lingua franca of data science and machine learning."}}</ref> It is widely taught as an introductory programming language.<ref>{{Cite journal |last1=Sultana |first1=Simon G. |last2=Reed |first2=Philip A. |date=2017 |title=Curriculum for an Introductory Computer Science Course: Identifying Recommendations from Academia and Industry |journal=The Journal of Technology Studies |volume=43 |issue=2 |pages=80–92 |doi=10.21061/jots.v43i2.a.3 |issn=1071-6084 |jstor=90023144}}</ref> Since 2003, Python has consistently ranked in the top ten of the most popular programming languages in the [[TIOBE Programming Community Index]], which ranks based on searches in 24 platforms.<ref>{{cite web |title=TIOBE Index |publisher=TIOBE |url=https://www.tiobe.com/tiobe-index/ |access-date=3 January 2023 |quote=The TIOBE Programming Community index is an indicator of the popularity of programming languages |archive-date=25 February 2018 |archive-url=https://web.archive.org/web/20180225101948/https://www.tiobe.com/tiobe-index/ |url-status=live}}</ref>

== History ==
{{Main|History of Python}}
[[File:Guido van Rossum in PyConUS24.jpg|thumb|311x311px|The designer of Python, [[Guido van Rossum]], at [[PyCon]] US 2024]]
Python was conceived in the late 1980s<ref name="venners-interview-pt-1" /> by [[Guido van Rossum]] at [[Centrum Wiskunde & Informatica]] (CWI) in the [[Netherlands]].<ref name="timeline-of-python" /> It was designed as a successor to the [[ABC (programming language)|ABC]] programming language, which was inspired by [[SETL]],<ref name="AutoNT-12" /> capable of [[exception handling]] and interfacing with the [[Amoeba (operating system)|Amoeba]] operating system.<ref name="faq-created" /> Python implementation began in December&nbsp;1989.<ref name="timeline-of-python" /> Van Rossum first released it in 1991 as Python&nbsp;0.9.0.<ref name="timeline-of-python" /> Van Rossum assumed sole responsibility for the project, as the lead developer, until 12 July 2018, when he announced his "permanent vacation" from responsibilities as Python's "[[benevolent dictator for life]]" (BDFL); this title was bestowed on him by the Python community to reflect his long-term commitment as the project's chief decision-maker.<ref name="lj-bdfl-resignation" /> (He has since come out of retirement and is self-titled "BDFL-emeritus"<!-- on his Twitter-->.) In January&nbsp;2019, active Python core developers elected a five-member Steering Council to lead the project.<ref>{{cite web |last1=Smith |first1=Nathaniel J. |last2=Durbin |first2=Ee |title=PEP 8100 – January 2019 Steering Council election |url=https://peps.python.org/pep-8100/ |url-status=live |archive-url=https://web.archive.org/web/20200604235027/https://www.python.org/dev/peps/pep-8100/ |archive-date=4 June 2020 |access-date=4 May 2019 |website=Python Enhancement Proposals (PEPs) |publisher=Python Software Foundation}}</ref><ref>{{Cite web |author=The Python core team and community |title=PEP 13 – Python Language Governance |url=https://peps.python.org/pep-0013/ |url-status=live |archive-url=https://web.archive.org/web/20210527000035/https://www.python.org/dev/peps/pep-0013/ |archive-date=27 May 2021 |access-date=25 August 2021 |website=Python Enhancement Proposals (PEPs) |language=en}}</ref>

The name ''Python'' derives from the British comedy series [[Monty Python's Flying Circus]].<ref name=":0">{{Cite book |last1=Briggs |first1=Jason R. |url=https://archive.org/details/pythonforkidspla0000brig |title=Python for kids: a playful introduction to programming |last2=Lipovača |first2=Miran |date=2013 |publisher=No Starch Press |isbn=978-1-59327-407-8 |location=San Francisco, California, USA |lccn=2012044047 |oclc=825076499 |ol=26119645M}}</ref> (See {{section link||Naming}}.)

Python 2.0 was released on 16 October 2000, featuring many new features such as [[list comprehension]]s, [[cycle detection|cycle-detecting]] garbage collection, [[reference counting]], and [[Unicode]] support.<ref name="newin-2.0" /> Python 2.7's [[end-of-life product|end-of-life]] was initially set for 2015, and then postponed to 2020 out of concern that a large body of existing code could not easily be forward-ported to Python&nbsp;3.<ref>{{cite web |last=Peterson |first=Benjamin |title=PEP 373 – Python 2.7 Release Schedule |url=https://legacy.python.org/dev/peps/pep-0373/ |url-status=live |archive-url=https://web.archive.org/web/20200519075520/https://legacy.python.org/dev/peps/pep-0373/ |archive-date=19 May 2020 |access-date=9 January 2017 |work=python.org}}</ref><ref>{{cite web |last=Coghlan |first=Alyssa |title=PEP 466 – Network Security Enhancements for Python 2.7.x |url=https://peps.python.org/pep-0466/ |url-status=live |archive-url=https://web.archive.org/web/20200604232833/https://www.python.org/dev/peps/pep-0466/ |archive-date=4 June 2020 |access-date=9 January 2017 |website=Python Enhancement Proposals (PEPs)}}</ref> It no longer receives security patches or updates.<ref>{{Cite web |title=Sunsetting Python 2 |url=https://www.python.org/doc/sunset-python-2/ |url-status=live |archive-url=https://web.archive.org/web/20200112080903/https://www.python.org/doc/sunset-python-2/ |archive-date=12 January 2020 |access-date=22 September 2019 |website=Python.org |language=en}}</ref><ref>{{Cite web |last=Peterson |first=Benjamin |title=PEP 373 – Python 2.7 Release Schedule |url=https://peps.python.org/pep-0373/ |url-status=live |archive-url=https://web.archive.org/web/20200113033257/https://www.python.org/dev/peps/pep-0373/ |archive-date=13 January 2020 |access-date=22 September 2019 |website=Python Enhancement Proposals (PEPs) |language=en}}</ref> While Python 2.7 and older versions are officially unsupported, a different unofficial Python implementation, [[PyPy]], continues to support Python 2, i.e., "2.7.18+" (plus 3.11<!-- PyPy docs in Nov 2025: "Python 2.7.18 and 3.11.11", not mentioning later 3.11.14 -->), with the plus signifying (at least some) "[[backporting|backported]] security updates".<ref>{{Cite web |last=mattip |date=25 December 2023 |title=PyPy v7.3.14 release |url=https://www.pypy.org/posts/2023/12/pypy-v7314-release.html |url-status=live |archive-url=https://web.archive.org/web/20240105132820/https://www.pypy.org/posts/2023/12/pypy-v7314-release.html |archive-date=5 January 2024 |access-date=5 January 2024 |website=PyPy |language=en}}</ref>

Python&nbsp;3.0 was released on 3 December 2008, and was a major revision and not completely [[backward-compatible]] with earlier versions, with some new semantics and changed syntax. Python&nbsp;2.7.18, released in 2020, was the last release of Python&nbsp;2.<ref>{{Cite web |last=Peterson |first=Benjamin |date=20 April 2020 |title=Python 2.7.18, the last release of Python 2 |url=https://pythoninsider.blogspot.com/2020/04/python-2718-last-release-of-python-2.html |url-status=live |archive-url=https://web.archive.org/web/20200426204118/https://pythoninsider.blogspot.com/2020/04/python-2718-last-release-of-python-2.html |archive-date=26 April 2020 |access-date=27 April 2020 |website=Python Insider}}</ref> Several releases in the Python 3.x series have added new syntax to the language, and made a few (considered very minor) backward-incompatible changes.

{{As of|December 2025}}, Python {{wikidata|property|P548=Q2804309|P348}} is the latest stable release. All older 3.x versions had a security update down to Python 3.9.24 then again with 3.9.25, the final version in 3.9 series. Python 3.10 is, since November 2025, the oldest supported branch.<ref>{{Cite web |title=Status of Python versions |url=https://devguide.python.org/versions/ |access-date=12 November 2025 |website=Python Developer's Guide |language=en}}</ref> Python 3.15 has an alpha released, and Android has an official downloadable executable available for Python 3.14. Releases receive two years of full support followed by three years of security support.

==Design philosophy and features==
Python is a [[multi-paradigm programming language]]. Object-oriented programming and structured programming are fully supported, and many of their features support functional programming and [[aspect-oriented programming]] – including [[metaprogramming]]<ref name=AutoNT-13/> and [[metaobject]]s.<ref name=AutoNT-14/> Many other paradigms are supported via extensions, including [[design by contract]]<ref name=AutoNT-15/><ref name=AutoNT-16/> and [[logic programming]].<ref name=AutoNT-17/> Python is often referred to as a <span style="margin-right: 2px">''[[glue language|<nowiki/>'glue language']]''</span><ref>{{cite web |title=Glue it all together with Python |url=https://www.python.org/doc/essays/omg-darpa-mcc-position/ |access-date=2024-09-30 |website=Python.org |language=en}}</ref> because it is purposely designed to be able to integrate components written in other languages.

Python uses dynamic typing and a combination of [[reference counting]] and a cycle-detecting garbage collector for [[memory management]].<ref name=Reference_counting>{{cite web |title=Reference counts |department=Extending and embedding the Python interpreter |website=Docs.python.org |language=en |url=https://docs.python.org/extending/extending.html#reference-counts |url-status=live |access-date=5 June 2020 |quote=Since Python makes heavy use of <code>malloc()</code> and <code>free()}</code>, it needs a strategy to avoid memory leaks as well as the re‑use of freed memory. The method chosen is called ''reference counting''. |archive-url=https://web.archive.org/web/20121018063230/http://docs.python.org/extending/extending.html#reference-counts |archive-date=18 October 2012 }}</ref> It uses dynamic [[Name resolution (programming languages)|name resolution]] ([[late binding]]), which binds method and variable names during program execution.

Python's design offers some support for functional programming in the "[[Lisp (programming language)|Lisp]] tradition". It has {{code|filter}}, {{code|map}}, and {{code|reduce}} functions; [[list comprehension]]s, [[associative array|dictionaries]], [[set (mathematics)|sets]], and [[generator (computer programming)|generator]] expressions.<ref name=AutoNT-59/> The standard library has two modules ({{codes|itertools}} and {{codes|functools}}) that implement functional tools borrowed from [[Haskell]] and [[Standard ML]].<ref name=AutoNT-18/>

Python's core philosophy is summarized in the [[Zen of Python]] (PEP 20) written by [[Tim Peters (software engineer)|Tim Peters]], which includes aphorisms such as these:<ref name=PEP20/>
* Explicit is better than implicit.
* Simple is better than complex.
* Readability counts.
* Special cases aren't special enough to break the rules.
* Although practicality beats purity,  errors should never pass silently, unless explicitly silenced.
* There should be one-- and preferably only one --obvious way to do it.
<!-- Note this isn't a full list, just some of the more significant aphorisms -->

However, Python has received criticism for violating these principles and adding unnecessary language bloat.<ref name=Python-Changes-2014>{{cite web |last=Lutz |first=Mark |date=January 2022 |website=Learning Python |title=Python changes 2014+ |url=https://learning-python.com/python-changes-2014-plus.html |url-status=live |access-date=25 February 2024 |archive-url=https://web.archive.org/web/20240315075935/https://learning-python.com/python-changes-2014-plus.html |archive-date=15 March 2024 }}</ref> Responses to these criticisms note that the Zen of Python is a guideline rather than a rule.<ref name=Confusion-regarding-a-rule-in-the-Zen-of-Python>{{cite web |url=https://discuss.python.org/t/confusion-regarding-a-rule-in-the-zen-of-python/15927 |title=Confusion regarding a rule in 'the Zen of Python' |date=2022-05-03 |department=Discussions |series=Python help |website=Python.org |access-date=2024-02-25 |archive-date=25 February 2024 |archive-url=https://web.archive.org/web/20240225221142/https://discuss.python.org/t/confusion-regarding-a-rule-in-the-zen-of-python/15927 |url-status=live}}</ref> The addition of some new features had been controversial: Guido van Rossum resigned as ''Benevolent Dictator for Life'' after conflict about adding the assignment expression operator in {{nobr|Python 3.8.}}<ref name=The-Most-Controversial-Python-Walrus-Operator>{{cite web |last=Ambi |first=Chetan |date=2021-07-04 |title=The most controversial Python 'walrus operator' |website=Python simplified (pythonsimplified.com) |url=https://pythonsimplified.com/the-most-controversial-python-walrus-operator/ |url-status=live |access-date=2024-02-05 |archive-url=https://web.archive.org/web/20230827154931/https://pythonsimplified.com/the-most-controversial-python-walrus-operator/ |archive-date=27 August 2023 }}</ref><ref name=The-Controversy-Behind-The-Walrus-Operator-in-Python>{{cite web |last=Grifski |first=Jeremy |date=2020-05-24 |title=The controversy behind the 'walrus operator' in Python |website=The Renegade Coder (therenegadecoder.com) |url=https://therenegadecoder.com/code/the-controversy-behind-the-walrus-operator-in-python/ |url-status=live |access-date=2024-02-25 |archive-url=https://web.archive.org/web/20231228135749/https://therenegadecoder.com/code/the-controversy-behind-the-walrus-operator-in-python/ |archive-date=28 December 2023 }}</ref>

Nevertheless, rather than building all functionality into its core, Python was designed to be highly [[extensible]] via modules. This compact modularity has made it particularly popular as a means of adding programmable interfaces to existing applications. Van Rossum's vision of a small core language with a large standard library and easily extensible interpreter stemmed from his frustrations with ABC, which represented the opposite approach.<ref name=venners-interview-pt-1/>

Python claims to strive for a simpler, less-cluttered syntax and grammar, while giving developers a choice in their coding methodology. Python lacks do while loops, which [[Guido Van Rossum|Rossum]] considered harmful.<ref>{{cite web|url=https://mail.python.org/pipermail/python-ideas/2013-June/021610.html|title=[Python-ideas] PEP 315: do-while |date=26 June 2013 }}</ref> In contrast to [[Perl]]'s motto "[[there is more than one way to do it]]", Python advocates an approach where "there should be one – and preferably only one – obvious way to do it".<!-- removed comment with specious demand to leave punctuation contrary to Wikipedia MOS unchanged: Reason given, to duplicate lack of spaces in quote, is a grotesquely false justification. --><ref name=PEP20/> In practice, however, Python provides many ways to achieve a given goal. There are at least three ways to format a string literal, with no certainty as to which one a programmer should use.<ref name=Python-String-Formatting-Best-Practices>{{cite web |last=Bader |first=Dan |title=Python string formatting best practices |website=Real Python (realpython.com) |url=https://realpython.com/python-string-formatting/ |url-status=live |access-date=2024-02-25 |archive-url=https://web.archive.org/web/20240218083506/https://realpython.com/python-string-formatting/ |archive-date=18 February 2024 }}</ref> [[Alex Martelli]] is a [[Fellow]] at the [[Python Software Foundation]] and Python book author; he wrote that "To describe something as 'clever' is ''not'' considered a compliment in the Python culture."<ref name=AutoNT-19/>

Python's developers typically prioritise readability over performance. For example, they reject patches to non-critical parts of the [[CPython]] reference implementation that would offer increases in speed that do not justify the cost of clarity and readability.<ref name="AutoNT-20"/>{{Failed verification|date=August 2025|reason=The referenced source did not mention that information. A better source should be found.}} Execution speed can be improved by moving speed-critical functions to extension modules written in languages such as [[C (programming language)|C]], or by using a [[just-in-time compiler]] like [[PyPy]]. Also, it is possible to transpile to other languages. However, this approach either fails to achieve the expected speed-up, since Python is a very [[dynamic language]], or only a restricted subset of Python is compiled (with potential minor semantic changes).<ref name=PyJL/>

Python is meant to be a fun language to use. This goal is reflected in the name – a tribute to the British comedy group [[Monty Python]]<ref name=whyname/> – and in playful approaches to some tutorials and reference materials. For instance, some code examples use the terms "spam" and "eggs" (in reference to [[Spam (Monty Python)|a Monty Python sketch]]), rather than the typical terms [[foobar|"foo" and "bar"]].<ref>{{cite web |title=15&nbsp;ways Python is a powerful force on the web |url=https://insidetech.monster.com/training/articles/8114-15-ways-python-is-a-powerful-force-on-the-web |access-date=3 July 2018 |archive-url=https://web.archive.org/web/20190511065650/http://insidetech.monster.com/training/articles/8114-15-ways-python-is-a-powerful-force-on-the-web |archive-date=11 May 2019 }}</ref><ref name=pprint-doc>{{cite web |title=<code>pprint</code> – data pretty printer – {{nobr|Python 3.11.0}} documentation |website=docs.python.org |quote=<code>stuff {{=}} ['spam', 'eggs', 'lumberjack', 'knights', 'ni']</code> |url=https://docs.python.org/3/library/pprint.html |url-status=live |access-date=2022-11-05 |archive-url=https://web.archive.org/web/20210122224848/https://docs.python.org/3/library/pprint.html |archive-date=22 January 2021 }}</ref>

A common [[neologism]] in the Python community is ''pythonic'', which has a broad range of meanings related to program style: Pythonic code may use Python [[Programming idiom|idioms]] well; be natural or show fluency in the language; or conform with Python's minimalist philosophy and emphasis on readability.<ref>{{cite web |title=Code style |department=The hitchhiker's guide to Python |website=docs.python-guide.org |url=https://docs.python-guide.org/writing/style |url-status=live |access-date=20 January 2021 |archive-url=https://web.archive.org/web/20210127154341/https://docs.python-guide.org/writing/style/ |archive-date=27 January 2021 }}</ref>

==Syntax and semantics==
{{Main|Python syntax and semantics}}
Python is meant to be an easily readable language. Its formatting is visually uncluttered and often uses English keywords where other languages use punctuation. Unlike many other languages, it does not use [[curly bracket programming language|curly brackets]] to delimit blocks, and semicolons after statements are allowed but rarely used. It has fewer syntactic exceptions and special cases than [[C (programming language)|C]] or [[Pascal (programming language)|Pascal]].<ref name="AutoNT-52"/>

===Indentation===
{{Further|Python syntax and semantics#Indentation}}

Python uses [[whitespace character|whitespace]] indentation, rather than curly brackets or keywords, to delimit [[block (programming)|blocks]]. An increase in indentation comes after certain statements; a decrease in indentation signifies the end of the current block.<ref name="AutoNT-53"/> Thus, the program's visual structure accurately represents its semantic structure.<ref name=guttag>{{Cite book |publisher=MIT Press |isbn=978-0-262-52962-4 |last=Guttag |first=John V. |title=Introduction to Computation and Programming Using Python: With Application to Understanding Data |date=12 August 2016}}</ref> This feature is sometimes termed the [[off-side rule]]. Some other languages use indentation this way; but in most, indentation has no semantic meaning. The recommended indent size is four spaces.<ref name="pep8">{{Cite web |first1=Guido  |last1= van Rossum |first2= Barry |last2=Warsaw |url=https://www.python.org/dev/peps/pep-0008/|title=PEP 8 – Style Guide for Python Code|website=Python Enhancement Proposals (PEPs)|access-date=26 March 2019|archive-date=17 April 2019|archive-url=https://web.archive.org/web/20190417223549/https://www.python.org/dev/peps/pep-0008/|url-status=live}}</ref>

===Statements and control flow===
Python's [[statement (computer science)|statements]] include the following:
* The [[Assignment (computer science)|assignment]] statement, using a single equals sign <code>=</code>
* The <code>[[if-then-else|if]]</code> statement, which conditionally executes a block of code, along with <code>[[Conditional (computer programming)#If–then(–else)|else]]</code> and <code>elif</code> (a contraction of <code>[[Conditional (computer programming)#Else if|else if]]</code>)
* The <code>[[Foreach#Python|for]]</code> statement, which iterates over an ''iterable'' object, capturing each element to a variable for use by the attached block; the variable is not deleted when the loop finishes
* The <code>[[While loop#Python|while]]</code> statement, which executes a block of code as long as boolean condition is true
* The <code>[[Exception handling syntax#Python|try]]</code> statement, which allows exceptions raised in its attached code block to be caught and handled by <code>except</code> clauses (or new syntax <code>except*</code> in Python 3.11 for exception groups);<ref>{{Cite web |title=8. Errors and Exceptions – Python 3.12.0a0 documentation |url=https://docs.python.org/3.11/tutorial/errors.html |access-date=2022-05-09 |website=docs.python.org |archive-date=9 May 2022 |archive-url=https://web.archive.org/web/20220509145745/https://docs.python.org/3.11/tutorial/errors.html |url-status=live}}</ref> the <code>try</code> statement also ensures that clean-up code in a <code>finally</code> block is always run regardless of how the block exits
* The <code>raise</code> statement, used to raise a specified exception or re-raise a caught exception
* The <code>class</code> statement, which executes a block of code and attaches its local namespace to a [[class (computer science)|class]], for use in object-oriented programming
* The <code>def</code> statement, which defines a [[function (computing)|function]] or [[method (computing)|method]]
* The <code>[[dispose pattern#Language constructs|with]]</code> statement, which encloses a code block within a context manager, allowing [[resource acquisition is initialization|resource-acquisition-is-initialization]] (RAII)-like behavior and replacing a common try/finally idiom<ref>{{cite web|url=https://www.python.org/download/releases/2.5/highlights/|title=Highlights: Python 2.5|website=Python.org|access-date=20 March 2018|archive-date=4 August 2019|archive-url=https://web.archive.org/web/20190804120408/https://www.python.org/download/releases/2.5/highlights/|url-status=live}}</ref> Examples of a context include acquiring a [[lock (computer science)|lock]] before some code is run, and then releasing the lock; or opening and then closing a [[Computer file|file]]
* The <code>[[break statement|break]]</code> statement, which exits a loop
* The <code>continue</code> statement, which skips the rest of the current iteration and continues with the next
* The <code>del</code> statement, which removes a variable—deleting the reference from the name to the value, and producing an error if the variable is referred to before it is redefined {{efn|<code>del</code> in Python does not behave the same way <code>delete</code> in languages such as [[C++]] does, where such a word is used to call the [[Destructor (computer programming)|destructor]] and deallocate heap memory.}} 
* The <code>pass</code> statement, serving as a [[NOP (code)|NOP]] (i.e., no operation), which is syntactically needed to create an empty code block
* The <code>[[assertion (programming)|assert]]</code> statement, used in debugging to check for conditions that should apply
* The <code>yield</code> statement, which returns a value from a [[generator (computer programming)#Python|generator]] function (and also an operator); used to implement [[coroutine]]s
* The <code>return</code> statement, used to return a value from a function
* The <code>[[include directive|import]]</code> and <code>from</code> statements, used to import modules whose functions or variables can be used in the current program
* The <code>match</code> and <code>case</code> statements, analogous to a [[switch statement]] construct, which compares an expression against one or more cases as a control-flow measure

The assignment statement (<code>=</code>) binds a name as a [[pointer (computer programming)|reference]] to a separate, dynamically allocated [[object (computer science)|object]]. Variables may subsequently be rebound at any time to any object. In Python, a variable name is a generic reference holder without a fixed [[Type system|data type]]; however, it always refers to ''some'' object with a type. This is called [[Type system#Dynamic type checking and runtime type information|dynamic typing]]—in contrast to [[statically-typed]] languages, where each variable may contain only a value of a certain type.

Python does not support [[tail call]] optimization or [[first-class continuations]]; according to Van Rossum, the language never will.<ref name="AutoNT-55"/><ref name="AutoNT-56"/> However, better support for [[coroutine]]-like functionality is provided by extending Python's generators.<ref name="AutoNT-57"/> Before 2.5, generators were [[lazy evaluation|lazy]] [[iterator]]s; data was passed unidirectionally out of the generator. From Python&nbsp;2.5 on, it is possible to pass data back into a generator function; and from version 3.3, data can be passed through multiple stack levels.<ref name="AutoNT-58"/>

===Expressions===
Python's [[expression (computer science)|expressions]] include the following:
* The <code>+</code>, <code>-</code>, and <code>*</code> operators for mathematical addition, subtraction, and multiplication are similar to other languages, but the behavior of division differs. There are two types of division in Python: [[floor division]] (or integer division) <code>//</code>, and floating-point division <code>/</code>.<ref>{{cite web|title=division|url=https://docs.python.org|website=python.org|access-date=30 July 2014|archive-date=20 July 2006|archive-url=https://web.archive.org/web/20060720033244/http://docs.python.org/|url-status=live}}</ref> Python uses the <code>**</code> operator for exponentiation.
* Python uses the <code>+</code> operator for string concatenation. The language uses the <code>*</code> operator for duplicating a string a specified number of times.
* The <code>@</code> infix operator<!-- was introduced in Python 3.5--> is intended to be used by libraries such as [[NumPy]] for [[matrix multiplication]].<ref name=PEP465>{{cite web |title=PEP 0465 – A dedicated infix operator for matrix multiplication |url=https://www.python.org/dev/peps/pep-0465/ |website=python.org |access-date=1 January 2016 |archive-date=4 June 2020 |archive-url=https://web.archive.org/web/20200604224255/https://www.python.org/dev/peps/pep-0465/ |url-status=live}}</ref><ref name=Python3.5Changelog>{{cite web |title=Python 3.5.1 Release and Changelog |url=https://www.python.org/downloads/release/python-351/ |website=python.org |access-date=1 January 2016 |archive-date=14 May 2020 |archive-url=https://web.archive.org/web/20200514034938/https://www.python.org/downloads/release/python-351/ |url-status=live}}</ref>
* The syntax <code>:=</code>, called the "{{va|walrus operator}}", was introduced in Python 3.8. This operator assigns values to variables as part of a larger expression.<ref name=Python3.8Changelog>{{cite web |title=What's New in Python 3.8 |url=https://docs.python.org/3.8/whatsnew/3.8.html |access-date=14 October 2019 |archive-date=8 June 2020 |archive-url=https://web.archive.org/web/20200608124345/https://docs.python.org/3.8/whatsnew/3.8.html |url-status=live}}</ref>
* In Python, <code>==</code> compares two objects by value. Python's <code>is</code> operator may be used to compare object identities (i.e., comparison by reference), and comparisons may be chained—for example, {{code|lang=python|code=a <= b <= c}}.
* Python uses <code>and</code>, <code>or</code>, and <code>not</code> as Boolean operators.
* Python has a type of expression called a ''[[List comprehension#Python|list comprehension]]'', and a more general expression called a ''generator expression''.<ref name="AutoNT-59"/>
* [[Anonymous function]]s are implemented using [[Lambda (programming)|lambda expressions]]; however, there may be only one expression in each body.
* Conditional expressions are written as {{code|lang=python|code=x if c else y}}.<ref name="AutoNT-60"/> (This is different in operand order from the <code>[[?:|c ? x : y]]</code> operator common to many other languages.)
* Python makes a distinction between [[list (computer science)|lists]] and [[tuple]]s. Lists are written as {{code|lang=python|code=[1, 2, 3]}}, are mutable, and cannot be used as the keys of dictionaries (since dictionary keys must be [[immutable]] in Python). Tuples, written as {{code|lang=python|code=(1, 2, 3)}}, are immutable and thus can be used as the keys of dictionaries, provided that all of the tuple's elements are immutable. The <code>+</code> operator can be used to concatenate two tuples, which does not directly modify their contents, but produces a new tuple containing the elements of both. For example, given the variable <code>t</code> initially equal to {{code|lang=python|code=(1, 2, 3)}}, executing {{code|lang=python|code=t = t + (4, 5)}} first evaluates {{code|lang=python|code=t + (4, 5)}}, which yields {{code|lang=python|code=(1, 2, 3, 4, 5)}}; this result is then assigned back to <code>t</code>—thereby effectively "modifying the contents" of <code>t</code> while conforming to the immutable nature of tuple objects. Parentheses are optional for tuples in unambiguous contexts.<ref>{{cite web|title=4. Built-in Types – Python 3.6.3rc1 documentation|url=https://docs.python.org/3/library/stdtypes.html#tuple|website=python.org|access-date=1 October 2017|archive-date=14 June 2020|archive-url=https://web.archive.org/web/20200614194325/https://docs.python.org/3/library/stdtypes.html#tuple|url-status=live}}</ref>
* Python features ''sequence unpacking'' where multiple expressions, each evaluating to something assignable (e.g., a variable or a writable property) are associated just as in forming tuple literal; as a whole, the results are then put on the left-hand side of the equal sign in an assignment statement. This statement expects an ''iterable'' object on the right-hand side of the equal sign to produce the same number of values as the writable expressions on the left-hand side; while iterating, the statement assigns each of the values produced on the right to the corresponding expression on the left.<ref>{{cite web|title=5.3. Tuples and Sequences – Python 3.7.1rc2 documentation|url=https://docs.python.org/3/tutorial/datastructures.html#tuples-and-sequences|website=python.org|access-date=17 October 2018|archive-date=10 June 2020|archive-url=https://web.archive.org/web/20200610050047/https://docs.python.org/3/tutorial/datastructures.html#tuples-and-sequences|url-status=live}}</ref>
* Python has a "string format" operator <code>%</code> that functions analogously to <code>[[printf]]</code> format strings in the C language—e.g. {{code|2=python|1="spam=%s eggs=%d" % ("blah", 2)}} evaluates to <code>"spam=blah eggs=2"</code>. In Python&nbsp;2.6+ and 3+, this operator was supplemented by the <code>format()</code> method of the <code>str</code> class, e.g., {{code|2=python|1="spam={0} eggs={1}".format("blah", 2)}}. Python&nbsp;3.6 added "f-strings": {{code|2=python|1=spam = "blah"; eggs = 2; f'spam={spam} eggs={eggs}'}}.<ref name="pep-0498">{{cite web |title=PEP 498 – Literal String Interpolation |url=https://www.python.org/dev/peps/pep-0498/ |website=python.org |access-date=8 March 2017 |archive-date=15 June 2020 |archive-url=https://web.archive.org/web/20200615184141/https://www.python.org/dev/peps/pep-0498/ |url-status=live}}</ref>
* Strings in Python can be [[concatenated]] by "adding" them (using the same operator as for adding integers and floats); e.g., {{code|2=python|1="spam" + "eggs"}} returns <code>"spameggs"</code>. If strings contain numbers, they are concatenated as strings rather than as integers, e.g. {{code|2=python|1="2" + "2"}} returns <code>"22"</code>.
* Python supports [[string literal]]s in several ways:
** Delimited by single or double quotation marks; single and double quotation marks have equivalent functionality (unlike in [[Unix shell]]s, [[Perl]], and Perl-influenced languages). Both marks use the backslash (<code>\</code>) as an [[escape character]]. [[String interpolation]] became available in Python&nbsp;3.6 as "formatted string literals".<ref name="pep-0498"/>
** Triple-quoted, i.e., starting and ending with three single or double quotation marks; this may span multiple lines and function like [[here document]]s in shells, Perl, and [[Ruby (programming language)|Ruby]].
** [[Raw string]] varieties, denoted by prefixing the string literal with <code>r</code>. Escape sequences are not interpreted; hence raw strings are useful where literal backslashes are common, such as in [[regular expression]]s and [[Windows]]-style paths. (Compare "<code>@</code>-quoting" in [[C Sharp (programming language)|C#]].)
* Python has [[array index]] and [[array slicing]] expressions in lists, which are written as <code>a[key]</code>, {{code|lang=python|code=a[start:stop]}} or {{code|lang=python|code=a[start:stop:step]}}. Indexes are [[zero-based numbering|zero-based]], and negative indexes are relative to the end. Slices take elements from the ''start'' index up to, but not including, the ''stop'' index. The (optional) third slice [[Parameter (computer programming)|parameter]], called ''step'' or ''stride'', allows elements to be skipped or reversed. Slice indexes may be omitted—for example, {{code|lang=python|code=a[:]}} returns a copy of the entire list. Each element of a slice is a [[shallow copy]].

In Python, a distinction between expressions and statements is rigidly enforced, in contrast to languages such as [[Common Lisp]], [[Scheme (programming language)|Scheme]], or [[Ruby (programming language)|Ruby]]. This distinction leads to duplicating some functionality, for example:
* [[List comprehensions]] vs. <code>for</code>-loops
* [[Conditional (programming)|Conditional]] expressions vs. <code>if</code> blocks
* The <code>eval()</code> vs. <code>exec()</code> built-in functions (in Python&nbsp;2, <code>exec</code> is a statement); the former function is for expressions, while the latter is for statements

A statement cannot be part of an expression; because of this restriction, expressions such as list and <code>dict</code> comprehensions (and lambda expressions) cannot contain statements. As a particular case, an assignment statement such as {{code|lang=python|code=a = 1}} cannot be part of the conditional expression of a conditional statement.

===Typing===
[[File:Python 3.13 Standrd Type Hierarchy-en.svg|thumb|The standard type hierarchy in Python&nbsp;3]]
Python uses [[duck typing]], and it has typed objects but untyped variable names. Type constraints are not checked at definition time; rather, operations on an object may fail at usage time, indicating that the object is not of an appropriate type. Despite being [[dynamically typed]], Python is [[strongly typed]], forbidding operations that are poorly defined (e.g., adding a number and a string) rather than quietly attempting to interpret them.

Python allows programmers to define their own types using [[class (computer science)|classes]], most often for [[object-oriented programming]]. New [[object (computer science)|instances]] of classes are constructed by calling the class, for example, {{code|lang=python|code=SpamClass()}} or {{code|lang=python|code=EggsClass()}}); the classes are instances of the [[metaclass]] <code>type</code> (which is an instance of itself), thereby allowing metaprogramming and [[Reflective programming|reflection]].

Before version 3.0, Python had two kinds of classes, both using the same syntax: ''old-style'' and ''new-style''.<ref name="classy"/> Current Python versions support the semantics of only the new style.

Python supports [[optional typing|optional type annotations]].<ref name="type_hint-PEP"/><ref>{{Cite web |title=PEP 484 – Type Hints {{!}} peps.python.org |url=https://peps.python.org/pep-0484/ |access-date=2023-11-29 |website=peps.python.org |archive-date=27 November 2023 |archive-url=https://web.archive.org/web/20231127205023/https://peps.python.org/pep-0484/ |url-status=live}}</ref> These annotations are not enforced by the language, but may be used by external tools such as '''mypy''' to catch errors. Python includes a module <code>typing</code> including several type names for type annotations.<ref>{{cite web |title=typing — Support for type hints |url=https://docs.python.org/3/library/typing.html |website=Python documentation |publisher=Python Software Foundation |access-date=22 December 2023 |archive-date=21 February 2020 |archive-url=https://web.archive.org/web/20200221184042/https://docs.python.org/3/library/typing.html |url-status=live}}</ref><ref>{{cite web |url=http://mypy-lang.org/ |title=mypy – Optional Static Typing for Python |access-date=28 January 2017 |archive-date=6 June 2020 |archive-url=https://web.archive.org/web/20200606192012/http://mypy-lang.org/ |url-status=live}}</ref> Also, Mypy supports a Python compiler called mypyc, which leverages type annotations for optimization.<ref>{{cite web |title=Introduction |url=https://mypyc.readthedocs.io/en/latest/introduction.html |website=mypyc.readthedocs.io |access-date=22 December 2023 |archive-date=22 December 2023 |archive-url=https://web.archive.org/web/20231222000457/https://mypyc.readthedocs.io/en/latest/introduction.html |url-status=live}}</ref>

{|class="wikitable"
|+ Summary of Python 3's built-in types
|-
! Type
! [[immutable object|Mutability]]
! Description
! Syntax examples
|-
| <code>bool</code>
| immutable
| [[Boolean value]]
| {{code|lang=python|True}}<br />{{code|lang=python|False}}
|-
| <code>bytearray</code>
| mutable
| Sequence of [[byte]]s
| {{code|lang=python|bytearray(b'Some ASCII')}}<br />{{code|lang=python|bytearray(b"Some ASCII")}}<br />{{code|lang=python|bytearray([119, 105, 107, 105])}}
|-
| <code>bytes</code>
| immutable
| Sequence of bytes
| {{code|lang=python|b'Some ASCII'}}<br />{{code|lang=python|b"Some ASCII"}}<br />{{code|lang=python|bytes([119, 105, 107, 105])}}
|-
| <code>complex</code>
| immutable
| [[Complex number]] with real and imaginary parts
| {{code|lang=python|3+2.7j}}<br />{{code|lang=python|3 + 2.7j}}<br />{{code|lang=python|5j}}
|-
| <code>dict</code>
| mutable
| [[Associative array]] (or dictionary) of key and value pairs; can contain mixed types (keys and values); keys must be a hashable type
| {{code|lang=python|{'key1': 1.0, 3: False} }}<br />{{code|lang=python| {} }}
|-
| <code>types.EllipsisType</code>
| immutable
| An [[Ellipsis (programming operator)|ellipsis]] placeholder to be used as an index in [[NumPy]] arrays
| {{code|lang=python|...}}<br />{{code|lang=python|Ellipsis}}
|-
| <code>float</code>
| immutable
| [[Double-precision]] [[floating-point number]]. The precision is machine-dependent, but in practice it is generally implemented as a 64-bit [[IEEE&nbsp;754]] number with 53&nbsp;bits of precision.<ref>{{Cite web
 |title=15. Floating Point Arithmetic: Issues and Limitations – Python 3.8.3 documentation
 |url=https://docs.python.org/3.8/tutorial/floatingpoint.html#representation-error
 |access-date=6 June 2020
 |website=docs.python.org
 |quote=Almost all machines today (November 2000) use IEEE-754 floating point arithmetic, and almost all platforms map Python floats to IEEE-754 "double precision".
 |archive-date=6 June 2020
 |archive-url=https://web.archive.org/web/20200606113842/https://docs.python.org/3.8/tutorial/floatingpoint.html#representation-error
 |url-status=live
}}</ref>
|
{{code|lang=python|1.33333}}
|-
| <code>frozenset</code>
| immutable
| Unordered [[set (computer science)|set]], contains no duplicates; can contain mixed types, if hashable
| {{code|lang=python|frozenset({4.0, 'string', True})}}
{{code|lang=python|frozenset()}}
|-
| <code>int</code>
| immutable
| [[Integer (computer science)|Integer]] of unlimited magnitude<ref name="pep0237"/>
| {{code|lang=python|42}}
|-
| <code>list</code>
| mutable
| [[list (computer science)|List]], can contain mixed types
| {{code|lang=python|[4.0, 'string', True]}}<br />{{code|lang=python|[]}}
|-
| <code>types.NoneType</code>
| immutable
| An object representing the absence of a value, often called [[null pointer|null]] in other languages
| {{code|lang=python|None}}
|-
| <code>types.NotImplementedType</code>
| immutable
| A placeholder that can be returned from [[Operator overloading|overloaded operators]] to indicate unsupported operand types.
| {{code|lang=python|NotImplemented}}
|-
| <code>range</code>
| immutable
| An ''immutable sequence'' of numbers, commonly used for iterating a specific number of times in <code>for</code> loops<ref>{{cite web |title=Built-in Types |url=https://docs.python.org/3/library/stdtypes.html#typesseq-range |access-date=3 October 2019 |archive-date=14 June 2020 |archive-url=https://web.archive.org/web/20200614194325/https://docs.python.org/3/library/stdtypes.html#typesseq-range |url-status=live}}</ref>
| {{code|lang=python|range(−1, 10)}}<br />{{code|lang=python|range(10, −5, −2)}}
|-
| <code>set</code>
| mutable
| Unordered [[set (computer science)|set]], contains no duplicates; can contain mixed types, if hashable
| {{code|lang=python| {4.0, 'string', True} }}<br />{{code|lang=python|set()}}
|-
| <code>str</code>
| immutable
| A [[character string]]: sequence of Unicode codepoints
| {{code|lang=python|'Wikipedia'}}<br />{{code|lang=python|"Wikipedia"}}<syntaxhighlight lang="python">"""Spanning
multiple
lines"""</syntaxhighlight>
|-
| <code>tuple</code>
| immutable
| [[Tuple]], can contain mixed types
| {{code|lang=python|(4.0, 'string', True)}}<br />{{code|lang=python|('single element',)}}<br />{{code|lang=python|()}}
|}

===Arithmetic operations===
Python includes conventional symbols for arithmetic operators (<code>+</code>, <code>-</code>, <code>*</code>, <code>/</code>), the floor-division operator <code>//</code>, and the [[modulo operation|modulo operator]] <code>%</code>. (With the modulo operator, a remainder can be negative,<!--unlike in C language depending on compiler,<ref>{{Cite web|url=https://stackoverflow.com/questions/11720656/modulo-operation-with-negative-numbers/42131603|title=c – Modulo operation with negative numbers|quote=Note that, in C89, whether the result round upward or downward is implementation-defined.|website=Stack Overflow|access-date=25 September 2019}}</ref>--> e.g., <code>4 % -3 == -2</code>.) Also, Python offers the <code>**</code> symbol for [[exponentiation]], e.g. <code>5**3 == 125</code> and <code>9**0.5 == 3.0</code>. Also, it offers the matrix‑multiplication operator <code>@</code> .<ref>{{cite web |url=https://legacy.python.org/dev/peps/pep-0465/ |title=PEP 465 – A dedicated infix operator for matrix multiplication |work=python.org |access-date=3 July 2018 |archive-date=29 May 2020 |archive-url=https://web.archive.org/web/20200529200310/https://legacy.python.org/dev/peps/pep-0465/ |url-status=live}}</ref> These operators work as in traditional mathematics; with the same [[order of operations|precedence rules]], the [[infix notation|infix]] operators <code>+</code> and <code>-</code> can also be [[unary operation|unary]], to represent positive and negative numbers respectively.

Division between integers produces floating-point results. The behavior of division has changed significantly over time:<ref name="pep0238"/>
* The current version of Python (i.e., since 3.0) changed the <code>/</code> operator to always represent floating-point division, e.g., {{code|class=nowrap|2=python|1=5/2 == 2.5}}.
* The floor division <code>//</code> operator was introduced, meaning that <code>7//3 == 2</code>, <code>-7//3 == -3</code>, <code>7.5//3 == 2.0</code>, and <code>-7.5//3 == -3.0</code>. For Python 2.7, adding the {{code|class=nowrap|2=python2|1=from __future__ import division}} statement allows a module in Python 2.7 to use Python 3.x rules for division (see above).

In Python terms, the <code>/</code> operator represents ''true division'' (or simply ''division''), while the <code>//</code> operator represents ''floor division.'' Before version 3.0, the <code>/</code> operator represents ''classic division''.<ref name="pep0238"/>

[[Rounding]] towards negative infinity, though a different method than in most languages, adds consistency to Python. For instance, this rounding implies that the equation {{code|class=nowrap|2=python|1=(a + b)//b == a//b + 1}} is always true. Also, the rounding implies that the equation {{code|class=nowrap|2=python|1=b*(a//b) + a%b == a}} is valid for both positive and negative values of <code>a</code>. As expected, the result of <code>a%b</code> lies in the [[half-open interval]] [0, ''b''), where <code>b</code> is a positive integer; however, maintaining the validity of the equation requires that the result must lie in the interval (''b'', 0] when <code>b</code> is negative.<ref name="AutoNT-62"/>

Python provides a <code>round</code> function for rounding a float to the nearest integer. For [[Rounding#Tie-breaking|tie-breaking]], Python&nbsp;3 uses the ''round to even'' method: <code>round(1.5)</code> and <code>round(2.5)</code> both produce <code>2</code>.<ref name="AutoNT-64"/> Python versions before 3 used the [[Rounding#Rounding away from zero|round-away-from-zero]] method: <code>round(0.5)</code> is <code>1.0</code>, and <code>round(-0.5)</code> is <code>−1.0</code>.<ref name="AutoNT-63"/>

Python allows Boolean expressions that contain multiple equality relations to be consistent with general usage in mathematics. For example, the expression <code>a < b < c</code> tests whether <code>a</code> is less than <code>b</code> and <code>b</code> is less than <code>c</code>.<ref name="AutoNT-65"/> C-derived languages interpret this expression differently: in C, the expression would first evaluate <code>a < b</code>, resulting in 0 or 1, and that result would then be compared with <code>c</code>.<ref name="CPL"/>

Python uses [[arbitrary-precision arithmetic]] for all integer operations. The <code>Decimal</code> type/class in the <code>decimal</code> module provides [[decimal floating point|decimal floating-point numbers]] to a pre-defined arbitrary precision with several rounding modes.<ref name="AutoNT-88"/> The <code>Fraction</code> class in the <code>fractions</code> module provides arbitrary precision for [[rational number]]s.<ref>{{cite web|title=What's New in Python 2.6 |url=https://docs.python.org/2.6/whatsnew/2.6.html|website=Python v2.6.9 documentation |date=Oct 29, 2013 |access-date=26 September 2015|archive-date=23 December 2019|archive-url=https://web.archive.org/web/20191223213856/https://docs.python.org/2.6/whatsnew/2.6.html|url-status=live}}</ref>

Due to Python's extensive mathematics library and the third-party library [[NumPy]], the language is frequently used for scientific scripting in tasks such as numerical data processing and manipulation.<ref>{{Cite web|url=https://www.stat.washington.edu/~hoytak/blog/whypython.html|title=10 Reasons Python Rocks for Research (And a Few Reasons it Doesn't) – Hoyt Koepke|website=University of Washington Department of Statistics |access-date=3 February 2019|archive-date=31 May 2020|archive-url=https://web.archive.org/web/20200531211840/https://www.stat.washington.edu/~hoytak/blog/whypython.html}}</ref><ref>{{Cite web|url=https://engineering.ucsb.edu/~shell/che210d/python.pdf|title=An introduction to Python for scientific computing|last=Shell|first=Scott|date=17 June 2014|access-date=3 February 2019|archive-date=4 February 2019|archive-url=https://web.archive.org/web/20190204014642/https://engineering.ucsb.edu/~shell/che210d/python.pdf|url-status=live}}</ref>

===Function syntax===
[[Function (computer programming)|Functions]] are created in Python by using the <code>def</code> keyword. A function is defined similarly to how it is called, by first providing the function name and then the required parameters. Here is an example of a function that prints its inputs:
<syntaxhighlight lang="python3">
def printer(input1, input2 = "already there"):
    print(input1)
    print(input2)
    
printer("hello")
    
# Example output:
# hello
# already there
</syntaxhighlight>To assign a default value to a function parameter in case no actual value is provided at run time, variable-definition syntax can be used inside the function header.

==Code examples==
[["Hello, World!" program]]:
<syntaxhighlight lang="python">
print('Hello, World!')
</syntaxhighlight>

Program to calculate the [[factorial]] of a non-negative integer:
<syntaxhighlight lang="python" line="1">
text = input('Type a number, and its factorial will be printed: ')
n = int(text)

if n < 0:
    raise ValueError('You must enter a non-negative integer')

factorial = 1
for i in range(2, n + 1):
    factorial *= i

print(factorial)

</syntaxhighlight><!--

Please don't add more examples.

-->

==Libraries==
Python's large standard library<ref name="AutoNT-86"/> is commonly cited as one of its greatest strengths. For Internet-facing applications, many standard formats and protocols such as [[MIME]] and [[HTTP]] are supported. The language includes modules for creating [[graphical user interface]]s, connecting to [[relational database]]s, [[pseudorandom number generator|generating pseudorandom numbers]], arithmetic with arbitrary-precision decimals,<ref name="AutoNT-88"/> manipulating [[regular expression]]s, and [[unit testing]].

Some parts of the standard library are covered by specifications—for example, the [[Web Server Gateway Interface]] (WSGI) implementation <code>wsgiref</code> follows PEP 333<ref name="AutoNT-89"/>—but most parts are specified by their code, internal documentation, and [[test suite]]s. However, because most of the standard library is cross-platform Python code, only a few modules must be altered or rewritten for variant implementations.

{{As of|2025|03|13|post=,}} the [[Python Package Index]] (PyPI), the official repository for third-party Python software, contains over 614,339<ref name="PyPI">{{cite web |date=2025-03-13 |title=PyPI |url=https://pypi.org/ |url-status=live |archive-url=https://web.archive.org/web/20250222013445/https://pypi.org/ |archive-date=2025-02-22 |website=PyPI}}</ref> packages.

==Development environments==
{{See also|Comparison of integrated development environments#Python}}

Most{{which?|date=August 2025}} Python implementations (including CPython) include a [[read–eval–print loop]] (REPL); this permits the environment to function as a [[command line interpreter]], with which users enter statements sequentially and receive results immediately.<ref>{{cite web |title=Glossary: interactive |url=https://docs.python.org/3/glossary.html#term-interactive |website=Python documentation |access-date=31 August 2025 |language=en |version=v3.13.7}}</ref>

Also, CPython is bundled with an [[integrated development environment|integrated development environment (IDE)]] called [[IDLE]],<ref name="idle">{{cite web |title=IDLE — Python editor and shell |url=https://docs.python.org/3/library/idle.html |website=Python documentation |version=v3.13.7 |access-date=31 August 2025 |language=en |quote=IDLE is Python's Integrated Development and Learning Environment.}}</ref> which is oriented toward beginners.{{cn|date=August 2025}}

Other shells, including [[IDLE]] and [[IPython]], add additional capabilities such as improved auto-completion, session-state retention, and [[syntax highlighting]].<ref name="idle" /><ref>{{cite web |title=IPython Documentation |url=https://ipython.readthedocs.io/en/stable/ |access-date=31 August 2025 |archive-url=https://web.archive.org/web/20250831204721/https://ipython.readthedocs.io/en/stable/ |archive-date=2025-08-31 |language=en |version=v9.5.0 |date=August 29, 2025 |url-status=live}}</ref>

Standard desktop IDEs include [[PyCharm]], [[Spyder (software)|Spyder]], and [[Visual Studio Code]]<ref>{{Cite web|title=Python in Visual Studio Code|url=https://code.visualstudio.com/docs/languages/python|website=code.visualstudio.com|access-date=2025-12-01|language=en}}</ref>;there are [[web browser]]-based IDEs, such as the following environments:

* [[Project Jupyter|Jupyter Notebooks]], an open-source interactive computing platform;<ref>{{cite web |title=Project Jupyter |url=https://jupyter.org |website=Jupyter.org |access-date=2 April 2025 |archive-date=12 October 2023 |archive-url=https://web.archive.org/web/20231012055917/https://jupyter.org/ |url-status=live}}</ref>
* [[PythonAnywhere]], a browser-based IDE and hosting environment; and
* Canopy, a commercial IDE from [[Enthought]] that emphasizes [[scientific computing]].<ref>{{cite web |last1=Harper |first1=Doug |title=Enthought Canopy |url=http://physics.wku.edu/phys316/software/canopy/ |website=WKU Physics 316 |publisher=[[Western Kentucky University]] |access-date=31 August 2025 |archive-url=https://web.archive.org/web/20240818041226/http://physics.wku.edu/phys316/software/canopy/ |archive-date=2024-08-18 |language=en |date=Spring 2024 |url-status=live}}</ref><ref>{{cite web|title=Enthought Canopy|url=https://www.enthought.com/products/canopy/|website=[[Enthought]]|access-date=20 August 2016|archive-date=15 July 2017|archive-url=https://web.archive.org/web/20170715151703/https://www.enthought.com/products/canopy/}}</ref>

==Implementations==
{{See also|List of Python software#Python implementations}}

===Reference implementation===
[[CPython]] is the [[reference implementation]] of Python. This implementation is written in C, meeting the [[C11 (C standard revision)|C11]] standard<ref>{{Cite web |title=PEP 7 – Style Guide for C Code {{!}} peps.python.org |url=https://peps.python.org/pep-0007/ |access-date=2022-04-28 |website=peps.python.org |archive-date=24 April 2022 |archive-url=https://web.archive.org/web/20220424202827/https://peps.python.org/pep-0007/ |url-status=live}}</ref> since version 3.11. Older versions use the [[C89 (C version)|C89]] standard with several select [[C99]] features, but third-party extensions are not limited to older C versions—e.g., they can be implemented using C11 or C++.<ref>{{Cite web|title=4. Building C and C++ Extensions – Python 3.9.2 documentation|url=https://docs.python.org/3/extending/building.html|access-date=2021-03-01|website=docs.python.org|archive-date=3 March 2021|archive-url=https://web.archive.org/web/20210303002519/https://docs.python.org/3/extending/building.html|url-status=live}}</ref><ref name="AutoNT-66"/> CPython [[compiler|compiles]] Python programs into an intermediate [[bytecode]],<ref name="AutoNT-67"/> which is then executed by a [[virtual machine]].<ref name="AutoNT-68"/> CPython is distributed with a large standard library written in a combination of C and native Python.

CPython is available for many platforms, including Windows and most modern [[Unix-like]] systems, including macOS (and [[Apple M1]] Macs, since Python&nbsp;3.9.1, using an experimental installer). <!-- "Windows Vista support dropped in Python 3.7" -->Starting with Python&nbsp;3.9, the Python installer intentionally fails to install on [[Windows 7]] and 8<!-- but not 8.1? -->;<ref>{{Cite web |title=Changelog – Python 3.9.0 documentation |url=https://docs.python.org/release/3.9.0/whatsnew/changelog.html#changelog |url-status=live |archive-url=https://web.archive.org/web/20210207001142/https://docs.python.org/release/3.9.0/whatsnew/changelog.html#changelog |archive-date=7 February 2021 |access-date=2021-02-08 |website=docs.python.org}}</ref><ref>{{Cite web |title=Download Python |url=https://www.python.org/downloads/release/python-391 |url-status=live |archive-url=https://web.archive.org/web/20201208045225/https://www.python.org/downloads/release/python-391/ |archive-date=8 December 2020 |access-date=2020-12-13 |website=Python.org |language=en}}</ref> [[Windows XP]] was supported until Python&nbsp;3.5<!--"Windows XP support dropped in Python 3.5"-->, with unofficial support for [[OpenVMS|VMS]].<!--"Put online a new version of Python 3.10.0a (IA64only)"--><ref>{{Cite web|title=history [vmspython]|url=https://www.vmspython.org/doku.php?id=history|access-date=2020-12-04|website=www.vmspython.org|archive-date=2 December 2020|archive-url=https://web.archive.org/web/20201202194743/https://www.vmspython.org/doku.php?id=history|url-status=live}}</ref> Platform portability was one of Python's earliest priorities.<ref name="AutoNT-69" /> During development of Python&nbsp;1 and 2, even [[OS/2]] and [[Solaris (operating system)|Solaris]] were supported;<!-- Also python-3.2.2 at http://unixpackages.com/packages/package-list --><ref name="DownloadOther"/><!-- older reference have access-date=2020-12-04 archive-date=27 November 2020 --> since that time, support has been dropped for many platforms.<!--

Starting with CPython 3.7.0, *nix platforms are expected to provide at least one of C.UTF-8 (full locale), C.utf8 (full locale) or UTF-8 (LC_CTYPE-only locale) as an alternative to the legacy C locale.
-->

All current Python versions (since 3.7) support only operating systems that feature multithreading<!-- (then in 3.7 removing support for [[IRIX]]; and before many other operating systems such as [[OS/2]] and [[VMS]]) -->, by now supporting not nearly as many operating systems (dropping many outdated) than in the past.

===Limitations of the reference implementation===
* The energy usage of Python with CPython for typically written code is much worse than C by a factor of 75.88.<ref name=":1">{{Cite book |last1=Pereira |first1=Rui |last2=Couto |first2=Marco |last3=Ribeiro |first3=Francisco |last4=Rua |first4=Rui |last5=Cunha |first5=Jácome |last6=Fernandes |first6=João Paulo |last7=Saraiva |first7=João |chapter=Energy efficiency across programming languages: How do energy, time, and memory relate? |date=2017-10-23 |title=Proceedings of the 10th ACM SIGPLAN International Conference on Software Language Engineering |chapter-url=https://doi.org/10.1145/3136014.3136031 |series=SLE 2017 |location=New York, NY, USA |publisher=Association for Computing Machinery |pages=256–267 |doi=10.1145/3136014.3136031 |isbn=978-1-4503-5525-4 |url=http://repositorio.inesctec.pt/handle/123456789/5492 }}</ref>
* The throughput of Python with CPython for typically written code is worse than C by a factor of 71.9.<ref name=":1" />
* The average memory usage of CPython for typically written code is worse than C by a factor of 2.4.<ref name=":1" />

===Other implementations===
All alternative implementations have at least slightly different semantics. For example, an alternative may include unordered dictionaries<!-- like with Codon; also PyPy? Cython? -->, in contrast to other current Python versions. As another example in the larger Python ecosystem, PyPy does not support the full C Python API.

Creating an executable with Python often is done by bundling an entire Python interpreter into the executable, which causes binary sizes to be massive for small programs,<ref>{{cite web|url=https://pyinstaller.org/en/stable/operating-mode.html|title=What PyInstaller Does and How It Does It}}</ref> yet there exist implementations that are capable of truly compiling Python. Alternative implementations include the following:

* [[PyPy]] is a faster, compliant interpreter of Python&nbsp;2.7 and <!-- 3.8 (both are outdated CPython versions) --> 3.10.<ref name="AutoNT-70"/><ref>{{Cite web|last=Team|first=The PyPy|date=2019-12-28|title=Download and Install|url=https://www.pypy.org/download.html|access-date=2022-01-08|website=PyPy|language=en|archive-date=8 January 2022|archive-url=https://web.archive.org/web/20220108212951/https://www.pypy.org/download.html|url-status=live}}</ref> PyPy's [[just-in-time compiler]] often improves speed significantly relative to CPython, but PyPy does not support some libraries written in C.<ref name="AutoNT-71"/> PyPy offers support for the [[RISC-V]] instruction-set architecture.
* Codon is an implementation with an [[ahead-of-time compilation|ahead-of-time (AOT) compiler]], which compiles a statically-typed Python-like language whose "syntax and semantics are nearly identical to Python's, there are some notable differences"<ref>{{Cite web |title=Codon: Differences with Python |url=https://docs.exaloop.io/codon/general/differences |url-status=live |archive-url=https://web.archive.org/web/20230525002540/https://docs.exaloop.io/codon/general/differences |archive-date=2023-05-25 |access-date=2023-08-28}}</ref> For example, Codon uses 64-bit machine integers for speed, not arbitrarily as with Python; Codon developers claim that speedups over CPython are usually on the order of ten to a hundred times. Codon compiles to machine code (via [[LLVM]]) and supports native multithreading.<ref>{{Cite web |last=Lawson |first=Loraine |date=2023-03-14 |title=MIT-Created Compiler Speeds up Python Code |url=https://thenewstack.io/mit-created-compiler-speeds-up-python-code/ |url-status=live |archive-url=https://web.archive.org/web/20230406054200/https://thenewstack.io/mit-created-compiler-speeds-up-python-code/ |archive-date=2023-04-06 |access-date=2023-08-28 |website=The New Stack |language=en-US}}</ref> <!-- It's compile has a restrictive BSL licence, but it doesn't affect generated code: --> Codon can also compile to Python extension modules that can be imported and used from Python.
* [[MicroPython]] and [[CircuitPython]] are Python&nbsp;3 variants that are optimized for [[microcontroller]]s, including the [[Lego Mindstorms EV3]].<ref>{{Cite web|url=https://education.lego.com/en-us/support/mindstorms-ev3/python-for-ev3|title=Python-for-EV3|website=LEGO Education|language=en|access-date=17 April 2019|archive-date=7 June 2020|archive-url=https://web.archive.org/web/20200607234814/https://education.lego.com/en-us/support/mindstorms-ev3/python-for-ev3|url-status=live}}</ref>
* Pyston is a variant of the Python runtime that uses just-in-time compilation to speed up execution of Python programs.<ref>{{cite news|url=https://www.infoworld.com/article/3587591/pyston-returns-from-the-dead-to-speed-python.html|title=Pyston returns from the dead to speed Python|last=Yegulalp|first=Serdar|date=29 October 2020|website=[[InfoWorld]]|access-date=26 January 2021|archive-date=27 January 2021|archive-url=https://web.archive.org/web/20210127113233/https://www.infoworld.com/article/3587591/pyston-returns-from-the-dead-to-speed-python.html|url-status=live}}</ref>
* Cinder is a performance-oriented fork of CPython 3.8 that features a number of optimizations, including bytecode inline caching, eager evaluation of coroutines, a method-at-a-time [[Just-in-time compilation|JIT]], and an experimental bytecode compiler.<ref>{{Cite web|url=https://github.com/facebookincubator/cinder|title=cinder: Instagram's performance-oriented fork of CPython.|website=[[GitHub]]|access-date=4 May 2021|language=en|archive-date=4 May 2021|archive-url=https://web.archive.org/web/20210504112500/https://github.com/facebookincubator/cinder|url-status=live}}</ref>
* The Snek<!-- (previously named Newt) --><ref>{{Cite web |last=Aroca |first=Rafael |date=2021-08-07 |title=Snek Lang: feels like Python on Arduinos |url=https://rafaelaroca.wordpress.com/2021/08/07/snek-lang-feels-like-python-on-arduinos/ |access-date=2024-01-04 |website=Yet Another Technology Blog |language=en |archive-date=5 January 2024 |archive-url=https://web.archive.org/web/20240105001031/https://rafaelaroca.wordpress.com/2021/08/07/snek-lang-feels-like-python-on-arduinos/ |url-status=live}}</ref><ref>{{Cite web |last=Aufranc (CNXSoft) |first=Jean-Luc |date=2020-01-16 |title=Snekboard Controls LEGO Power Functions with CircuitPython or Snek Programming Languages (Crowdfunding) – CNX Software |url=https://www.cnx-software.com/2020/01/16/snekboard-controls-lego-power-functions-with-circuitpython-or-snek-programming-languages/ |access-date=2024-01-04 |website=CNX Software – Embedded Systems News |language=en-US |archive-date=5 January 2024 |archive-url=https://web.archive.org/web/20240105001031/https://www.cnx-software.com/2020/01/16/snekboard-controls-lego-power-functions-with-circuitpython-or-snek-programming-languages/ |url-status=live}}</ref><ref>{{Cite web |last=Kennedy (@mkennedy) |first=Michael |title=Ready to find out if you're git famous? |url=https://pythonbytes.fm/episodes/show/187/ready-to-find-out-if-youre-git-famous |access-date=2024-01-04 |website=pythonbytes.fm |language=en-US |archive-date=5 January 2024 |archive-url=https://web.archive.org/web/20240105001031/https://pythonbytes.fm/episodes/show/187/ready-to-find-out-if-youre-git-famous |url-status=live}}</ref><!-- https://keithp.com/blogs/newt-lola/ https://bipes.net.br/snek-web-uploader/ --> embedded computing language "is Python-inspired, but it is not Python. It is possible to write Snek programs that run under a full Python system, but most Python programs will not run under Snek."<ref>{{Cite web |last=Packard |first=Keith |date=2022-12-20 |title=The Snek Programming Language: A Python-inspired Embedded Computing Language |url=https://sneklang.org/doc/snek.pdf |access-date=4 January 2024 |archive-date=4 January 2024 |archive-url=https://web.archive.org/web/20240104162458/https://sneklang.org/doc/snek.pdf |url-status=live}}</ref> Snek is compatible with 8-bit [[AVR microcontrollers]] such as [[ATmega|ATmega 328P]]-based Arduino, as well as larger microcontrollers that are compatible with [[MicroPython]]. Snek is an imperative language that (unlike Python) omits [[object-oriented programming]]. Snek supports only one numeric data type, which features 32-bit [[single-precision|single precision]] (resembling [[JavaScript]] numbers, though smaller).<!-- "Snek is a tiny embeddable language targeting processors with only a few kB of flash and ram. Think of something that would have been running BASIC years ago and you'll have the idea. These processors are too small to run MicroPython." "Snekboard is a custom embedded computer designed to run Snek or CircuitPython." -->

===Unsupported implementations===
[[Stackless Python]] is a significant fork of CPython that implements [[microthread]]s. This implementation uses the [[call stack]] differently, thus allowing massively concurrent programs. PyPy also offers a stackless version.<ref name="AutoNT-73"/>

Just-in-time Python compilers have been developed, but are now unsupported:
* Google began a project named [[Unladen Swallow]] in 2009: this project aimed to speed up the Python interpreter five-fold by using [[LLVM]], and improve [[multithreading (computer architecture)|multithreading]] capability for scaling to thousands of cores,<ref name="AutoNT-74"/> while typical implementations are limited by the [[global interpreter lock]].
* [[Psyco]] is a discontinued [[just-in-time compilation|just-in-time]] [[run-time algorithm specialization|specializing]] compiler, which integrates with CPython and transforms bytecode to machine code at runtime. The emitted code is specialized for certain [[data type]]s and is faster than standard Python code. Psyco does not support Python&nbsp;2.7 or later.
* [[PyS60]] was a Python&nbsp;2 interpreter for [[Series 60]] mobile phones, which was released by [[Nokia]] in 2005. The interpreter implemented many modules from Python's standard library, as well as additional modules for integration with the [[Symbian]] operating system. The Nokia [[N900]] also supports Python through the [[GTK]] widget library, allowing programs to be written and run on the target device.<ref>{{cite web|title=Python on the Nokia N900|url=http://www.stochasticgeometry.ie/2010/04/29/python-on-the-nokia-n900/|website=Stochastic Geometry|date=29 April 2010|access-date=9 July 2015|archive-date=20 June 2019|archive-url=https://web.archive.org/web/20190620000053/http://www.stochasticgeometry.ie/2010/04/29/python-on-the-nokia-n900/|url-status=live}}</ref>

===Transpilers to other languages===
There are several compilers/[[transpiler]]s to high-level object languages; the source language is unrestricted Python, a subset of Python, or a language similar to Python:
* Brython<ref>{{Cite web|title=Brython|url=https://brython.info/|access-date=2021-01-21|website=brython.info|archive-date=3 August 2018|archive-url=https://web.archive.org/web/20180803065954/http://brython.info/|url-status=live}}</ref> and Transcrypt<ref>{{cite web|title=Transcrypt – Python in the browser|url=https://www.transcrypt.org|access-date=22 December 2020|website=transcrypt.org|language=en|archive-date=19 August 2018|archive-url=https://web.archive.org/web/20180819133303/http://www.transcrypt.org/|url-status=live}}</ref><ref>{{Cite web|url=https://www.infoq.com/articles/transcrypt-python-javascript-compiler/|title=Transcrypt: Anatomy of a Python to JavaScript Compiler|website=InfoQ|access-date=20 January 2021|archive-date=5 December 2020|archive-url=https://web.archive.org/web/20201205193339/https://www.infoq.com/articles/transcrypt-python-javascript-compiler/|url-status=live}}</ref> compile Python to [[JavaScript]].
* [[Cython]] compiles a superset of Python<!-- actually 2.7 by default, but Python 3 by override --> to C. The resulting code can be used with Python via direct C-level API calls into the Python interpreter.
* PyJL compiles/transpiles a subset of Python to "human-readable, maintainable, and high-performance Julia source code".<ref name=PyJL>{{Cite web|title=Transpiling Python to Julia using PyJL|url=https://web.ist.utl.pt/antonio.menezes.leitao/ADA/documents/publications_docs/2022_TranspilingPythonToJuliaUsingPyJL.pdf|quote=After manually modifying one line of code by specifying the necessary type information, we obtained a speedup of 52.6×, making the translated Julia code 19.5× faster than the original Python code.|access-date=20 September 2023|archive-date=19 November 2023|archive-url=https://web.archive.org/web/20231119071525/https://web.ist.utl.pt/antonio.menezes.leitao/ADA/documents/publications_docs/2022_TranspilingPythonToJuliaUsingPyJL.pdf|url-status=live}}</ref> Despite the developers' performance claims, this is not possible for ''arbitrary'' Python code; that is, compiling to a faster language or machine code is known to be impossible in the general case. The semantics of Python might potentially be changed, but in many cases speedup is possible with few or no changes in the Python code. The faster Julia source code can then be used from Python or compiled to machine code.
* [[Nuitka]] compiles Python into C<!-- "is the optimizing Python compiler written in Python that creates executables that run without a separate installer"-->.<ref>{{cite web|title=Nuitka Home {{!}} Nuitka Home|url=http://nuitka.net/|access-date=18 August 2017|website=nuitka.net|language=en|archive-date=30 May 2020|archive-url=https://web.archive.org/web/20200530211233/https://nuitka.net/|url-status=live}}</ref> This compiler works with Python 3.4 to 3.13 (and 2.6 and 2.7) for Python's main supported platforms (and Windows 7 or even Windows XP) and for Android. The compiler developers claim full support for Python 3.10, <!-- "also finishes full compatibility with the match statements of 3.10"  "From here on, we need to re-visit compatibility. A few more obscured 3.10 features are missing, the 3.11 compatibility is not yet complete" -->partial support for Python 3.11 and 3.12, <!-- "This release bumps the long-awaited 3.12 support to a complete level. Now, Nuitka behaves identically to CPython 3.12 for the most part. .. After being late with 3.12 support, we will now be early with 3.13 support if all goes well." --> and experimental support for Python 3.13. Nuitka supports macOS including Apple Silicon-based versions. <!-- "While arm64 (M1) only builds and x86_64 (Intel) only builds work, the value universal which of course implies twice the size, and as such has other disadvantages, is not yet supported. --> The compiler is free of cost, though it has commercial add-ons (e.g., for hiding source code).<!-- "Container Builds (public + commercial)" -->
* [[Numba]] is a JIT compiler that is used from Python; the compiler translates a subset of Python and NumPy code into fast machine code. This tool is enabled by adding a decorator to the relevant Python code.
* Pythran compiles a subset of Python&nbsp;3 to C++ ([[C++11]]).<ref name="Guelton Brunet Amini Merlini 2015 p=014001">{{cite journal |last1=Guelton |first1=Serge |last2=Brunet |first2=Pierrick |last3=Amini |first3=Mehdi |last4=Merlini |first4=Adrien |last5=Corbillon |first5=Xavier |last6=Raynaud |first6=Alan |title=Pythran: enabling static optimization of scientific Python programs |journal=Computational Science & Discovery |publisher=IOP Publishing |volume=8 |issue=1 |date=16 March 2015 |issn=1749-4699 |doi=10.1088/1749-4680/8/1/014001|doi-access=free |article-number=014001 |bibcode=2015CS&D....8a4001G}}</ref>
* [[RPython]] can be compiled to C, and it is used to build the PyPy interpreter for Python.
* The Python → 11l → C++ transpiler<ref>{{Cite web |url=https://11l-lang.org/transpiler |title=The Python → 11l → C++ transpiler |access-date=17 July 2022 |archive-date=24 September 2022 |archive-url=https://web.archive.org/web/20220924233728/https://11l-lang.org/transpiler/ |url-status=live}}</ref> compiles a subset of Python&nbsp;3 to C++ ([[C++17]]).

There are also specialized compilers:
* [[MyHDL]] is a Python-based [[hardware description language]] (HDL) that converts MyHDL code to [[Verilog]] or [[VHDL]] code.

Some older projects existed, as well as compilers not designed for use with Python 3.x and related syntax:
* Google's Grumpy [[transpile]]s Python&nbsp;2 to [[Go (programming language)|Go]].<ref>{{Cite web|url=https://github.com/google/grumpy|title=google/grumpy|date=10 April 2020|via=GitHub|access-date=25 March 2020|archive-date=15 April 2020|archive-url=https://web.archive.org/web/20200415054919/https://github.com/google/grumpy|url-status=live}}</ref><ref>{{Cite web|url=https://opensource.google/projects/|title=Projects|website=opensource.google|access-date=25 March 2020|archive-date=24 April 2020|archive-url=https://web.archive.org/web/20200424191248/https://opensource.google/projects/|url-status=live}}</ref><ref>{{Cite news|url=https://www.theregister.com/2017/01/05/googles_grumpy_makes_python_go/|title=Google's Grumpy code makes Python Go|first=Thomas Claburn in San|last=Francisco|website=www.theregister.com|access-date=20 January 2021|archive-date=7 March 2021|archive-url=https://web.archive.org/web/20210307165521/https://www.theregister.com/2017/01/05/googles_grumpy_makes_python_go/|url-status=live}}</ref> The latest release was in 2017.
* [[IronPython]]<!-- (abandoned by Microsoft) --> allows running Python&nbsp;2.7 programs with the .NET [[Common Language Runtime]].<ref>{{Cite web|title=IronPython.net /|url=https://ironpython.net/|website=ironpython.net|archive-date=17 April 2021|archive-url=https://web.archive.org/web/20210417064418/https://ironpython.net/|url-status=live}}</ref> An [[Software release life cycle#Alpha|alpha]] version (released in 2021), is available for "Python&nbsp;3.4, although features and behaviors from later versions may be included."<ref>{{Cite web |url=https://github.com/IronLanguages/ironpython3 |title=GitHub – IronLanguages/ironpython3: Implementation of Python 3.x for .NET Framework that is built on top of the Dynamic Language Runtime<!-- Bot generated title --> |website=[[GitHub]] |archive-date=28 September 2021 |archive-url=https://web.archive.org/web/20210928101250/https://github.com/IronLanguages/ironpython3 |url-status=live}}</ref>
* [[Jython]] compiles Python&nbsp;2.7 to Java bytecode, allowing the use of Java libraries from a Python program.<ref>{{Cite web|title=Jython FAQ|url=https://www.jython.org/jython-old-sites/archive/22/userfaq.html|access-date=2021-04-22|website=www.jython.org|archive-date=22 April 2021|archive-url=https://web.archive.org/web/20210422055726/https://www.jython.org/jython-old-sites/archive/22/userfaq.html|url-status=live}}</ref>
* [[Pyrex (programming language)|Pyrex]] (last released in 2010) and [[Shed Skin]] (last released in 2013) compile to C and C++ respectively.

===Performance===
A performance comparison among various Python implementations, using a non-numerical (combinatorial) workload, was presented at EuroSciPy '13.<ref>{{cite conference |title=Performance of Python runtimes on a non-numeric scientific code |last=Murri |first=Riccardo |conference=European Conference on Python in Science (EuroSciPy) |year=2013 |arxiv=1404.6388|bibcode=2014arXiv1404.6388M}}</ref> In addition, Python's performance relative to other programming languages is benchmarked by [[The Computer Language Benchmarks Game]].<ref>{{cite web|title=The Computer Language Benchmarks Game|url=https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/python.html|access-date=30 April 2020|archive-date=14 June 2020|archive-url=https://web.archive.org/web/20200614210246/https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/python.html|url-status=live}}</ref>

There are several approaches to optimizing Python performance, despite the inherent slowness of an [[interpreted language]]. These approaches include the following strategies or tools:

* [[Just-in-time compilation]]: Dynamically compiling parts of a Python program during the execution of the program. This technique is used in libraries such as [[Numba]] and [[PyPy]].
* [[Compiler|Static compilation]]: Sometimes, Python code can be compiled into machine code sometime before execution. An example of this approach is [[Cython]], which compiles Python into C.
* [[Concurrent computing|Concurrency]] and [[Parallel computing|parallelism]]: Multiple tasks can be run simultaneously. Python contains modules such as `multiprocessing` to support this form of parallelism. Moreover, this approach helps to overcome limitations of the [[Global interpreter lock|Global Interpreter Lock]] (GIL) in CPU tasks.
* Efficient [[data structures]]: Performance can also be improved by using data types such as <code>Set</code> for membership tests, or <code>deque</code> from <code>collections</code> for [[Queueing theory|queue]] operations.
* Performance gains can be observed by utilizing libraries such as [[NumPy]]. Most high performance Python libraries use [[C (programming language)|C]] or [[Fortran]] under the hood instead of the Python interpreter.<ref>{{Cite web |last=Python |first=Real |title=Look Ma, No for Loops: Array Programming With NumPy – Real Python |url=https://realpython.com/numpy-array-programming/ |access-date=2025-10-15 |website=realpython.com |language=en}}</ref>   

==Language Development==
Python's development is conducted mostly through the ''Python Enhancement Proposal'' (PEP) process; this process is the primary mechanism for proposing major new features, collecting community input on issues, and documenting Python design decisions.<ref name="PepCite000"/> Python coding style is covered in PEP&nbsp;8.<ref name="pep8"/> Outstanding PEPs are reviewed and commented on by the Python community and the steering council.<ref name="PepCite000"/>

Enhancement of the language corresponds with development of the CPython reference implementation. The mailing list python-dev is the primary forum for the language's development. Specific issues were originally discussed in the [[Roundup (issue tracker)|Roundup]] [[bug tracker]] hosted by the foundation.<ref name="AutoNT-21"/> In 2022, all issues and discussions were migrated to [[GitHub]].<ref>{{cite web |last1=Edge |first1=Jake |url=https://lwn.net/Articles/885854/ |title=Moving Python's bugs to GitHub &#91;LWN.net&#93; |date=23 February 2022 |access-date=2 October 2022 |archive-date=2 October 2022 |archive-url=https://web.archive.org/web/20221002183818/https://lwn.net/Articles/885854/ |url-status=live}}</ref> Development originally took place on a [[Self-hosting (web services)|self-hosted]] source-code repository running [[Mercurial]], until Python moved to [[GitHub]] in January 2017.<ref name=py_dev_guide>{{Cite web|url=https://devguide.python.org/|title=Python Developer's Guide – Python Developer's Guide|website=devguide.python.org|access-date=17 December 2019|archive-date=9 November 2020|archive-url=https://web.archive.org/web/20201109032501/https://devguide.python.org/|url-status=live}}</ref>

CPython's public releases have three types, distinguished by which part of the version number is incremented:
* ''Backward-incompatible versions'', where code is expected to break and must be manually [[ported]]. The first part of the version number is incremented. These releases happen infrequently—version 3.0 was released 8 years after 2.0. According to Guido van Rossum, a version 4.0 will probably never exist.<ref>{{Cite web |last=Hughes |first=Owen |date=2021-05-24 |title=Programming languages: Why Python 4.0 might never arrive, according to its creator |url=https://www.techrepublic.com/article/programming-languages-why-python-4-0-will-probably-never-arrive-according-to-its-creator/ |access-date=2022-05-16 |website=TechRepublic |language=en-US |archive-date=14 July 2022 |archive-url=https://web.archive.org/web/20220714201302/https://www.techrepublic.com/article/programming-languages-why-python-4-0-will-probably-never-arrive-according-to-its-creator/ |url-status=live}}</ref>
* ''Major or "feature" releases'' are largely compatible with the previous version but introduce new features. The second part of the version number is incremented. Starting with Python&nbsp;3.9, these releases are expected to occur annually.<ref>{{Cite web|url=https://www.python.org/dev/peps/pep-0602/|title=PEP 602 – Annual Release Cycle for Python|website=Python.org|language=en|access-date=6 November 2019|archive-date=14 June 2020|archive-url=https://web.archive.org/web/20200614202755/https://www.python.org/dev/peps/pep-0602/|url-status=live}}</ref><ref>{{Cite web|last1=Edge |first1=Jake |url=https://lwn.net/Articles/802777/|title=Changing the Python release cadence [LWN.net]|website=lwn.net|date=23 October 2019 |access-date=6 November 2019|archive-date=6 November 2019|archive-url=https://web.archive.org/web/20191106170153/https://lwn.net/Articles/802777/|url-status=live}}</ref> Each major version is supported by bug fixes for several years after its release.<ref name="release-schedule"/>
* ''Bug fix releases'',<ref name="AutoNT-22"/> which introduce no new features, occur approximately every three months; these releases are made when a sufficient number of bugs have been fixed [[Upstream (software development)|upstream]] since the last release. Security vulnerabilities are also patched in these releases. The third and final part of the version number is incremented.<ref name="AutoNT-22"/>

Many [[beta release|alpha, beta, and release-candidates]] are also released as previews and for testing before final releases. Although there is a rough schedule for releases, they are often delayed if the code is not ready yet. Python's development team monitors the state of the code by running a large [[unit test]] suite during development.<ref name="AutoNT-23"/>

The major [[academic conference]] on Python is [[PyCon]]. Also, there are special Python mentoring programs, such as [[PyLadies]].

==Naming==
Python's name is inspired by the British comedy group [[Monty Python]], whom Python creator Guido van Rossum enjoyed while developing the language. Monty Python references appear frequently in Python code and culture;<ref name="tutorial-chapter1"/> for example, the [[metasyntactic variable]]s often used in Python literature are [[Spam (Monty Python)|''spam'' and ''eggs'']], rather than the traditional [[foobar|''foo'' and ''bar'']].<ref name="tutorial-chapter1"/><ref name="AutoNT-26"/> Also, the official Python documentation contains various references to Monty Python routines.{{sfn|Lutz|2013|p=17}}<ref>{{cite book |last1=Fehily |first1=Chris |title=Python |year=2002 |publisher=Peachpit Press |isbn=978-0-201-74884-0 |page=xv |url=https://books.google.com/books?id=carqdIdfVlYC&pg=PR15 |language=en |access-date=9 May 2017 |archive-date=17 July 2017 |archive-url=https://web.archive.org/web/20170717044040/https://books.google.com/books?id=carqdIdfVlYC&pg=PR15 |url-status=live}}</ref> Python users are sometimes referred to as "Pythonistas".<ref name="introducing_python">{{Cite book |publisher=Sebastopol, CA : O'Reilly Media |isbn=978-1-4493-5936-2 |last=Lubanovic |first=Bill |title=Introducing Python |access-date=2023-07-31 |date=2014 |url=http://archive.org/details/introducingpytho0000luba |page=305}}</ref>

==Languages influenced by Python==
* [[Cobra (programming language)|Cobra]] has an ''Acknowledgements'' document that lists Python first among influencing languages.<ref>{{cite web |url=http://cobra-language.com/docs/acknowledgements/ |title=Acknowledgements |last=Esterbrook |first=Charles |work=cobra-language.com |publisher=Cobra Language |access-date=7 April 2010 |archive-date=8 February 2008 |archive-url=https://web.archive.org/web/20080208141002/http://cobra-language.com/docs/acknowledgements/ |url-status=dead}}</ref>
* [[ECMAScript]] and [[JavaScript]] borrowed iterators and [[generator (computer science)|generators]] from Python.<ref>{{cite web |url=http://wiki.ecmascript.org/doku.php?id=proposals:iterators_and_generators |archive-url=https://web.archive.org/web/20071020082650/http://wiki.ecmascript.org/doku.php?id=proposals:iterators_and_generators |url-status=dead |archive-date=20 October 2007 |title=Proposals: iterators and generators [ES4 Wiki&#93; |publisher=wiki.ecmascript.org |access-date=24 November 2008}}</ref>
* [[Go (programming language)|Go]] is designed for "speed of working in a dynamic language like Python".<ref>{{cite news |url=https://techcrunch.com/2009/11/10/google-go-language/ |title=Google's Go: A New Programming Language That's Python Meets C++ |last=Kincaid |first=Jason |date=10 November 2009 |work=TechCrunch |access-date=29 January 2010 |archive-date=18 January 2010 |archive-url=https://web.archive.org/web/20100118014358/http://www.techcrunch.com/2009/11/10/google-go-language/ |url-status=live}}</ref>
* [[Julia (programming language)|Julia]] was designed to be "as usable for general programming as Python".<ref>{{cite web |title= Why We Created Julia |date= February 2012 |website= Julia website |url= https://julialang.org/blog/2012/02/why-we-created-julia |access-date= 5 June 2014 |quote= We want something as usable for general programming as Python [...] |archive-date= 2 May 2020 |archive-url= https://web.archive.org/web/20200502144010/https://julialang.org/blog/2012/02/why-we-created-julia/ |url-status= live}}</ref>
* [[Mojo (programming language)|Mojo]] is almost<ref name="Mojo"/><ref>{{Cite web |title=Modular Docs – Why Mojo |url=https://docs.modular.com/mojo/why-mojo.html |access-date=2023-05-05 |website=docs.modular.com |language=en |quote=Mojo as a member of the Python family [..] Embracing Python massively simplifies our design efforts, because most of the syntax is already specified.  [..] we decided that the right long-term goal for Mojo is to provide a superset of Python (i.e. be compatible with existing programs) and to embrace the CPython immediately for long-tail ecosystem enablement. To a Python programmer, we expect and hope that Mojo will be immediately familiar, while also providing new tools for developing systems-level code that enable you to do things that Python falls back to C and C++ for. |archive-date=5 May 2023 |archive-url=https://web.archive.org/web/20230505083518/https://docs.modular.com/mojo/why-mojo.html |url-status=live}}</ref> a superset of Python.<ref>{{Cite web |last=Spencer |first=Michael |title=What is Mojo Programming Language? |url=https://datasciencelearningcenter.substack.com/p/what-is-mojo-programming-language |access-date=2023-05-05 |website=datasciencelearningcenter.substack.com |date=4 May 2023 |language=en |archive-date=5 May 2023 |archive-url=https://web.archive.org/web/20230505090408/https://datasciencelearningcenter.substack.com/p/what-is-mojo-programming-language |url-status=live}}</ref>
* [[GDScript]] is strongly influenced by Python.<ref>{{Cite web |title=GDScript |url=https://gdscript.com/ |access-date=2025-11-24 |website=gdscript.com}}</ref>
* [[Apache Groovy| Groovy]], [[Boo (programming language)|Boo]], [[CoffeeScript]], [[F Sharp (programming language)|F#]], [[Nim (programming language)|Nim]], [[Ring (programming language)|Ring]],<ref name="The Ring programming language and other languages"></ref> [[Ruby (programming language)|Ruby]],<ref name="bini"></ref> [[Swift (programming language)|Swift]],<ref name="lattner2014"></ref> and [[V (programming language)|V]]<ref name="vpeople"></ref> have been influenced, as well.

==See also==
{{Portal|Computer programming|Free and open-source software}}
* [[List of computer books#Python|List of Python programming books]]
* [[pip (package manager)]]
* [[Pydoc]]
* [[NumPy]]
* [[SciPy]]
* [[Jupyter]]
* [[Pytorch]]
* [[Cython]]
* [[CPython]]
* [[Mojo (programming language)|Mojo]]
* [[Pygame]]
* [[PyQt]]
* [[PyGTK]]
* [[PyPy]]
* [[PyCon]]
* [[Google Colab]]{{snd}} zero setup [[Online integrated development environment|online IDE]] that runs Python

{{Clear}}

==Notes==
{{Notelist}}

==References==
{{reflist|25em|refs=

<ref name="faq-created">{{cite web |url=https://docs.python.org/faq/general.html#why-was-python-created-in-the-first-place |title=Why was Python created in the first place? |work=General Python FAQ |publisher=Python Software Foundation |access-date=22 March 2007 |archive-date=24 October 2012 |archive-url=https://web.archive.org/web/20121024164224/http://docs.python.org/faq/general.html#why-was-python-created-in-the-first-place |url-status=live |quote=I had extensive experience with implementing an interpreted language in the ABC group at CWI, and from working with this group I had learned a lot about language design. This is the origin of many Python features, including the use of indentation for statement grouping and the inclusion of very high-level data types (although the details are all different in Python).}}</ref>

<ref name="98-interview">{{cite web |url=http://www.amk.ca/python/writing/gvr-interview |title=Interview with Guido van Rossum (July 1998) |last=Kuchling |first=Andrew M. |work=amk.ca |date=22 December 2006 |access-date=12 March 2012 |archive-url=https://web.archive.org/web/20070501105422/http://www.amk.ca/python/writing/gvr-interview |archive-date=1 May 2007 |quote=I'd spent a summer at DEC's Systems Research Center, which introduced me to Modula-2+; the Modula-3 final report was being written there at about the same time. What I learned there later showed up in Python's exception handling, modules, and the fact that methods explicitly contain 'self' in their parameter list. String slicing came from Algol-68 and Icon.}}</ref>

<ref name="AutoNT-1">{{cite journal |last=van Rossum |first=Guido |year=1993 |title=An Introduction to Python for UNIX/C Programmers |journal=Proceedings of the NLUUG Najaarsconferentie (Dutch UNIX Users Group) |quote=even though the design of C is far from ideal, its influence on Python is considerable. |citeseerx=10.1.1.38.2023}}</ref>

<ref name="classmix">{{cite web |url=https://docs.python.org/tutorial/classes.html |title=Classes |work=The Python Tutorial |publisher=Python Software Foundation |access-date=20 February 2012 |quote=It is a mixture of the class mechanisms found in C++ and Modula-3 |archive-date=23 October 2012 |archive-url=https://web.archive.org/web/20121023030209/http://docs.python.org/tutorial/classes.html |url-status=live}}</ref>

<ref name="effbot-call-by-object">{{cite web |url=http://effbot.org/zone/call-by-object.htm |title=Call By Object |work=effbot.org |last=Lundh |first=Fredrik |quote=replace "CLU" with "Python", "record" with "instance", and "procedure" with "function or method", and you get a pretty accurate description of Python's object model. |access-date=21 November 2017 |archive-date=23 November 2019 |archive-url=https://web.archive.org/web/20191123043655/http://effbot.org/zone/call-by-object.htm |url-status=live}}</ref>

<ref name="AutoNT-2">{{cite web |url=https://www.python.org/download/releases/2.3/mro/ |title=The Python 2.3 Method Resolution Order |last=Simionato |first=Michele |publisher=Python Software Foundation |quote=The C3 method itself has nothing to do with Python, since it was invented by people working on Dylan and it is described in a paper intended for lispers |access-date=29 July 2014 |archive-date=20 August 2020 |archive-url=https://web.archive.org/web/20200820231854/https://www.python.org/download/releases/2.3/mro/ |url-status=live}}</ref>

<ref name="AutoNT-3">{{cite web |url=https://docs.python.org/howto/functional.html |title=Functional Programming HOWTO |last=Kuchling |first=A. M. |work=Python v2.7.2 documentation |publisher=Python Software Foundation |quote=List comprehensions and generator expressions [...] are a concise notation for such operations, borrowed from the functional programming language Haskell. |access-date=9 February 2012 |archive-date=24 October 2012 |archive-url=https://web.archive.org/web/20121024163217/http://docs.python.org/howto/functional.html |url-status=live}}</ref>

<ref name="pep0238">{{cite web |url=https://www.python.org/dev/peps/pep-0238/ |title=PEP 238&nbsp;– Changing the Division Operator |first1=Moshe |last1=Zadka |first2=Guido |last2=van Rossum |date=11 March 2001 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=23 October 2013 |archive-date=28 May 2020 |archive-url=https://web.archive.org/web/20200528115550/https://www.python.org/dev/peps/pep-0238/ |url-status=live}}</ref>

<ref name="AutoNT-4">{{cite web |url=https://www.python.org/dev/peps/pep-0255/ |title=PEP 255&nbsp;– Simple Generators |first1=Neil |last1=Schemenauer |first2=Tim |last2=Peters |first3=Magnus Lie |last3=Hetland |date=18 May 2001 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=9 February 2012 |archive-date=5 June 2020 |archive-url=https://web.archive.org/web/20200605012926/https://www.python.org/dev/peps/pep-0255/ |url-status=live}}</ref>

<ref name="AutoNT-6">{{cite web |url=https://docs.python.org/3.2/tutorial/controlflow.html |title=More Control Flow Tools |work=Python 3 documentation |publisher=Python Software Foundation |access-date=24 July 2015 |archive-date=4 June 2016 |quote=By popular demand, a few features commonly found in functional programming languages like Lisp have been added to Python. With the lambda keyword, small anonymous functions can be created. |archive-url=https://web.archive.org/web/20160604080843/https://docs.python.org/3.2/tutorial/controlflow.html |url-status=live}}</ref>

<ref name="bini">{{cite book |last=Bini |first=Ola |title=Practical JRuby on Rails Web 2.0 Projects: bringing Ruby on Rails to the Java platform |year=2007 |publisher=APress |location=Berkeley |isbn=978-1-59059-881-8 |page=[https://archive.org/details/practicaljrubyon0000bini/page/3 3] |url-access=registration |url=https://archive.org/details/practicaljrubyon0000bini/page/3}}</ref>

<ref name="AutoNT-7">{{cite web |last=Kuhlman |first=Dave |url=https://www.davekuhlman.org/python_book_01.pdf|title=A Python Book: Beginning Python, Advanced Python, and Python Exercises |at=Section 1.1|archive-url=https://web.archive.org/web/20120623165941/http://cutter.rexx.com/~dkuhlman/python_book_01.html |archive-date=23 June 2012}}</ref>

<ref name="venners-interview-pt-1">{{cite web |url=http://www.artima.com/intv/pythonP.html |title=The Making of Python |last=Venners |first=Bill |date=13 January 2003 |work=Artima Developer |publisher=Artima |access-date=22 March 2007 |archive-date=1 September 2016 |archive-url=https://web.archive.org/web/20160901183332/http://www.artima.com/intv/pythonP.html |url-status=live}}</ref>

<ref name="timeline-of-python">{{cite web |url=https://python-history.blogspot.com/2009/01/brief-timeline-of-python.html |title=A Brief Timeline of Python |last=van Rossum |first=Guido |date=20 January 2009 |work=The History of Python |access-date=20 January 2009 |archive-date=5 June 2020 |archive-url=https://web.archive.org/web/20200605032200/https://python-history.blogspot.com/2009/01/brief-timeline-of-python.html |url-status=live}}</ref>

<ref name="AutoNT-12">{{cite mailing list |url=https://mail.python.org/pipermail/python-dev/2000-August/008881.html |title=SETL (was: Lukewarm about range literals) |date=29 August 2000 |access-date=13 March 2011 |mailing-list=Python-Dev |last=van Rossum |first=Guido |author-link=Guido van Rossum |archive-date=14 July 2018 |archive-url=https://web.archive.org/web/20180714064019/https://mail.python.org/pipermail/python-dev/2000-August/008881.html |url-status=live}}</ref>

<ref name="newin-2.0">{{cite web |url=https://docs.python.org/whatsnew/2.0.html |title=What's New in Python 2.0 |last1=Kuchling |first1=A. M. |last2=Zadka |first2=Moshe |date=16 October 2000 |publisher=Python Software Foundation |access-date=11 February 2012 |archive-date=23 October 2012 |archive-url=https://web.archive.org/web/20121023112045/http://docs.python.org/whatsnew/2.0.html |url-status=live}}</ref>

<ref name="AutoNT-13">{{cite web |url=https://www.python.org/community/pycon/dc2004/papers/24/metaclasses-pycon.pdf |archive-url=https://web.archive.org/web/20090530030205/http://www.python.org/community/pycon/dc2004/papers/24/metaclasses-pycon.pdf |archive-date=30 May 2009 |title=Python Metaclasses: Who? Why? When? |last=The Cain Gang Ltd. |access-date=27 June 2009 }}</ref>

<ref name="AutoNT-14">{{cite web |url=https://docs.python.org/3.0/reference/datamodel.html#special-method-names |title=3.3. Special method names |work=The Python Language Reference |publisher=Python Software Foundation |access-date=27 June 2009 |archive-date=15 December 2018 |archive-url=https://web.archive.org/web/20181215123146/https://docs.python.org/3.0/reference/datamodel.html#special-method-names |url-status=live}}</ref>

<ref name="AutoNT-15">{{cite web |url=http://www.nongnu.org/pydbc/ |title=PyDBC: method preconditions, method postconditions and class invariants for Python |access-date=24 September 2011 |archive-date=23 November 2019 |archive-url=https://web.archive.org/web/20191123231931/http://www.nongnu.org/pydbc/ |url-status=live}}</ref>

<ref name="AutoNT-16">{{cite web |url=http://www.wayforward.net/pycontract/ |title=Contracts for Python |access-date=24 September 2011 |archive-date=15 June 2020 |archive-url=https://web.archive.org/web/20200615173404/http://www.wayforward.net/pycontract/ |url-status=live}}</ref>

<ref name="AutoNT-17">{{cite web |url=https://sites.google.com/site/pydatalog/ |title=PyDatalog |access-date=22 July 2012 |archive-date=13 June 2020 |archive-url=https://web.archive.org/web/20200613160231/https://sites.google.com/site/pydatalog/ |url-status=live}}</ref>

<ref name="AutoNT-18">{{cite web |url=https://docs.python.org/3/library/itertools.html |title=6.5 itertools&nbsp;– Functions creating iterators for efficient looping |publisher=Docs.python.org |access-date=22 November 2016 |archive-date=14 June 2020 |archive-url=https://web.archive.org/web/20200614153629/https://docs.python.org/3/library/itertools.html |url-status=live}}</ref>

<ref name="PEP20">{{cite web |url=https://www.python.org/dev/peps/pep-0020/ |title=PEP 20&nbsp;– The Zen of Python |last=Peters |first=Tim |date=19 August 2004 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=24 November 2008 |archive-date=26 December 2018 |archive-url=https://web.archive.org/web/20181226141127/https://www.python.org/dev/peps/pep-0020/ |url-status=live}}</ref>

<ref name="AutoNT-19">{{cite book |url=http://shop.oreilly.com/product/9780596007973.do |title=Python Cookbook, 2nd Edition |publisher=[[O'Reilly Media]] |last1=Martelli |first1=Alex |last2=Ravenscroft |first2=Anna |last3=Ascher |first3=David |year=2005 |page=230 |isbn=978-0-596-00797-3 |access-date=14 November 2015 |archive-date=23 February 2020 |archive-url=https://web.archive.org/web/20200223171254/http://shop.oreilly.com/product/9780596007973.do |url-status=live}}</ref>

<ref name="AutoNT-20">{{cite web |title=Python Culture |website=ebeab |date=January 21, 2014 |url=http://ebeab.com/2014/01/21/python-culture/ |archive-url=https://web.archive.org/web/20140130021902/http://ebeab.com/2014/01/21/python-culture/ |archive-date=January 30, 2014 }}</ref>

<ref name="PepCite000">{{cite web |url=https://www.python.org/dev/peps/pep-0001/ |title=PEP 1&nbsp;– PEP Purpose and Guidelines |last1=Warsaw |first1=Barry |last2=Hylton |first2=Jeremy |last3=Goodger |first3=David |date=13 June 2000 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=19 April 2011 |archive-date=6 June 2020 |archive-url=https://web.archive.org/web/20200606042011/https://www.python.org/dev/peps/pep-0001/ |url-status=live}}</ref>

<ref name="AutoNT-21">{{cite web |url=https://www.python.org/dev/intro/ |title=Guido, Some Guys, and a Mailing List: How Python is Developed |last=Cannon |first=Brett |work=python.org |publisher=Python Software Foundation |access-date=27 June 2009 |archive-url=https://web.archive.org/web/20090601134342/http://www.python.org/dev/intro/ |archive-date=1 June 2009}}</ref>

<ref name="release-schedule">{{cite web |url=https://mail.python.org/pipermail/python-dev/2002-April/022739.html |title=&#91;Python-Dev&#93; Release Schedules (was Stability & change) |last=Norwitz |first=Neal |date=8 April 2002 |access-date=27 June 2009 |archive-date=15 December 2018 |archive-url=https://web.archive.org/web/20181215122750/https://mail.python.org/pipermail/python-dev/2002-April/022739.html |url-status=live}}</ref>

<ref name="AutoNT-22">{{cite web |url=https://www.python.org/dev/peps/pep-0006/ |title=PEP 6&nbsp;– Bug Fix Releases |last1=Aahz |last2=Baxter |first2=Anthony |date=15 March 2001 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=27 June 2009 |archive-date=5 June 2020 |archive-url=https://web.archive.org/web/20200605001318/https://www.python.org/dev/peps/pep-0006/ |url-status=live}}</ref>

<ref name="AutoNT-23">{{cite web |url=https://www.python.org/dev/buildbot/ |title=Python Buildbot |work=Python Developer's Guide |publisher=Python Software Foundation |access-date=24 September 2011 |archive-date=5 June 2020 |archive-url=https://web.archive.org/web/20200605001322/https://www.python.org/dev/buildbot/ |url-status=live}}</ref>

<ref name="whyname">{{cite web |url=https://docs.python.org/3/faq/general.html#why-is-it-called-python |title=Why is it called Python?|work=General Python FAQ |publisher=Docs.python.org |access-date=3 January 2023|archive-date=24 October 2012 |archive-url=https://web.archive.org/web/20121024164224/http://docs.python.org/faq/general.html#why-is-it-called-python |url-status=live}}</ref>

<ref name="tutorial-chapter1">{{cite web |url=https://docs.python.org/tutorial/appetite.html |title=Whetting Your Appetite |work=The Python Tutorial |publisher=Python Software Foundation |access-date=20 February 2012 |archive-date=26 October 2012 |archive-url=https://web.archive.org/web/20121026063559/http://docs.python.org/tutorial/appetite.html |url-status=live}}</ref>

<ref name="AutoNT-26">{{cite web |url=https://stackoverflow.com/questions/5033906/in-python-should-i-use-else-after-a-return-in-an-if-block |title=In Python, should I use else after a return in an if block? |date=17 February 2011 |work=[[Stack Overflow]] |publisher=Stack Exchange |access-date=6 May 2011 |archive-date=20 June 2019 |archive-url=https://web.archive.org/web/20190620000050/https://stackoverflow.com/questions/5033906/in-python-should-i-use-else-after-a-return-in-an-if-block |url-status=live}}</ref>

<ref name="AutoNT-52">{{cite web |title=Is Python a good language for beginning programmers? |url=https://docs.python.org/faq/general.html#is-python-a-good-language-for-beginning-programmers |work=General Python FAQ |publisher=Python Software Foundation |access-date=21 March 2007 |archive-date=24 October 2012 |archive-url=https://web.archive.org/web/20121024164224/http://docs.python.org/faq/general.html#is-python-a-good-language-for-beginning-programmers |url-status=live}}</ref>

<ref name="AutoNT-53">{{cite web |url=http://www.secnetix.de/~olli/Python/block_indentation.hawk |title=Myths about indentation in Python |publisher=Secnetix.de |access-date=19 April 2011 |archive-date=18 February 2018 |archive-url=https://web.archive.org/web/20180218162410/http://www.secnetix.de/~olli/Python/block_indentation.hawk }}</ref>

<ref name="AutoNT-55">{{cite web |last=van Rossum |first=Guido |url=http://neopythonic.blogspot.be/2009/04/tail-recursion-elimination.html |title=Tail Recursion Elimination |publisher=Neopythonic.blogspot.be |date=22 April 2009 |access-date=3 December 2012 |archive-date=19 May 2018 |archive-url=https://web.archive.org/web/20180519225253/http://neopythonic.blogspot.be/2009/04/tail-recursion-elimination.html |url-status=live}}</ref>

<ref name="AutoNT-56">{{cite web |title=Language Design Is Not Just Solving Puzzles |url=http://www.artima.com/weblogs/viewpost.jsp?thread=147358 |first=Guido |last=van Rossum |date=9 February 2006 |access-date=21 March 2007 |work=Artima forums |publisher=Artima |archive-date=17 January 2020 |archive-url=https://web.archive.org/web/20200117182525/https://www.artima.com/weblogs/viewpost.jsp?thread=147358 |url-status=live}}</ref>

<ref name="AutoNT-57">{{cite web |url=https://www.python.org/dev/peps/pep-0342/ |title=PEP 342&nbsp;– Coroutines via Enhanced Generators |last1=van Rossum |first1=Guido |last2=Eby |first2=Phillip J. |date=10 May 2005 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=19 February 2012 |archive-date=29 May 2020 |archive-url=https://web.archive.org/web/20200529003739/https://www.python.org/dev/peps/pep-0342/ |url-status=live}}</ref>

<ref name="AutoNT-58">{{cite web |url=https://www.python.org/dev/peps/pep-0380/ |title=PEP 380 |publisher=Python.org |access-date=3 December 2012 |archive-date=4 June 2020 |archive-url=https://web.archive.org/web/20200604233821/https://www.python.org/dev/peps/pep-0380/ |url-status=live}}</ref>

<ref name="AutoNT-59">{{cite web |url=https://www.python.org/dev/peps/pep-0289/ |title=PEP 289&nbsp;– Generator Expressions |last=Hettinger |first=Raymond |date=30 January 2002 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=19 February 2012 |archive-date=14 June 2020 |archive-url=https://web.archive.org/web/20200614153717/https://www.python.org/dev/peps/pep-0289/ |url-status=live}}</ref>

<ref name="AutoNT-60">{{cite web |url=https://www.python.org/dev/peps/pep-0308/ |title=PEP 308&nbsp;– Conditional Expressions |last1=van Rossum |first1=Guido |last2=Hettinger |first2=Raymond |date=7 February 2003 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=13 July 2011 |archive-date=13 March 2016 |archive-url=https://web.archive.org/web/20160313113147/https://www.python.org/dev/peps/pep-0308/ |url-status=live}}</ref>

<ref name="classy">{{cite web |title=The Python Language Reference, section 3.3. New-style and classic classes, for release 2.7.1 |access-date=12 January 2011 |url=https://docs.python.org/reference/datamodel.html#new-style-and-classic-classes |archive-date=26 October 2012 |archive-url=https://web.archive.org/web/20121026063834/http://docs.python.org/reference/datamodel.html#new-style-and-classic-classes }}</ref>

<ref name="pep0237">{{cite web |url=https://www.python.org/dev/peps/pep-0237/ |title=PEP 237&nbsp;– Unifying Long Integers and Integers |last1=Zadka |first1=Moshe |last2=van Rossum |first2=Guido |date=11 March 2001 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=24 September 2011 |archive-date=28 May 2020 |archive-url=https://web.archive.org/web/20200528063237/https://www.python.org/dev/peps/pep-0237/ |url-status=live}}</ref>

<ref name="AutoNT-62">{{cite web |url=https://python-history.blogspot.com/2010/08/why-pythons-integer-division-floors.html |title=Why Python's Integer Division Floors |date=24 August 2010 |access-date=25 August 2010 |archive-date=5 June 2020 |archive-url=https://web.archive.org/web/20200605151500/https://python-history.blogspot.com/2010/08/why-pythons-integer-division-floors.html |url-status=live}}</ref>

<ref name="AutoNT-63">{{citation |url=https://docs.python.org/library/functions.html#round |access-date=14 August 2011 |title=round |work=The Python standard library, release 2.7, §2: Built-in functions |archive-date=27 October 2012 |archive-url=https://web.archive.org/web/20121027081602/http://docs.python.org/library/functions.html#round |url-status=live}}</ref>

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<ref name="AutoNT-65">{{cite book |title=Python Essential Reference |url=https://archive.org/details/pythonessentialr00beaz_036 |url-access=limited |first1=David M. |last1=Beazley |edition=4th |year=2009 |page=[https://archive.org/details/pythonessentialr00beaz_036/page/n90 66] |publisher=Addison-Wesley Professional |isbn=978-0-672-32978-4}}</ref>

<ref name="CPL">{{cite book |title=The C Programming Language |first1=Brian W. |last1=Kernighan |first2=Dennis M. |last2=Ritchie |title-link=The C Programming Language |edition=2nd |year=1988 |page=[https://archive.org/details/cprogramminglang00bria/page/206 206]}}</ref>

<ref name="AutoNT-66">{{cite web |url=https://www.python.org/dev/peps/pep-0007/ |title=PEP 7&nbsp;– Style Guide for C Code |last=van Rossum |first=Guido |date=5 June 2001 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=24 November 2008 |archive-date=1 June 2020 |archive-url=https://web.archive.org/web/20200601203908/https://www.python.org/dev/peps/pep-0007/ |url-status=live}}</ref>

<ref name="AutoNT-67">{{cite web |url=https://docs.python.org/3/library/dis.html#python-bytecode-instructions |title=CPython byte code |publisher=Docs.python.org |access-date=16 February 2016 |archive-date=5 June 2020 |archive-url=https://web.archive.org/web/20200605151542/https://docs.python.org/3/library/dis.html#python-bytecode-instructions |url-status=live}}</ref>

<ref name="AutoNT-68">{{cite web |url=http://www.troeger.eu/teaching/pythonvm08.pdf |title=Python 2.5 internals |access-date=19 April 2011 |archive-date=6 August 2012 |archive-url=https://web.archive.org/web/20120806094951/http://www.troeger.eu/teaching/pythonvm08.pdf |url-status=live}}</ref>

<ref name="AutoNT-69">{{cite web |url=http://www.oreilly.com/pub/a/oreilly/frank/rossum_1099.html |title=An Interview with Guido van Rossum |publisher=Oreilly.com |access-date=24 November 2008 |archive-date=16 July 2014 |archive-url=https://web.archive.org/web/20140716222652/http://oreilly.com/pub/a/oreilly/frank/rossum_1099.html |url-status=live}}</ref>

<ref name="AutoNT-70">{{cite web |url=https://pypy.org/compat.html |title=PyPy compatibility |publisher=Pypy.org |access-date=3 December 2012 |archive-date=6 June 2020 |archive-url=https://web.archive.org/web/20200606041845/https://www.pypy.org/compat.html |url-status=live}}</ref>

<ref name="AutoNT-71">{{cite web |url=https://speed.pypy.org/ |title=speed comparison between CPython and Pypy |publisher=Speed.pypy.org |access-date=3 December 2012 |archive-date=10 May 2021 |archive-url=https://web.archive.org/web/20210510014902/https://speed.pypy.org/ |url-status=live}}</ref>

<ref name="AutoNT-73">{{cite web |url=http://doc.pypy.org/en/latest/stackless.html |title=Application-level Stackless features – PyPy 2.0.2 documentation |publisher=Doc.pypy.org |access-date=17 July 2013 |archive-date=4 June 2020 |archive-url=https://web.archive.org/web/20200604231513/https://doc.pypy.org/en/latest/stackless.html |url-status=live}}</ref>

<ref name="AutoNT-74">{{cite web |url=https://code.google.com/p/unladen-swallow/wiki/ProjectPlan |title=Plans for optimizing Python |work=Google Project Hosting |date=15 December 2009 |access-date=24 September 2011 |archive-date=11 April 2016 |archive-url=https://web.archive.org/web/20160411181848/https://code.google.com/p/unladen-swallow/wiki/ProjectPlan |url-status=live}}</ref>

<ref name="AutoNT-86">{{cite web |first=Przemyslaw |last=Piotrowski |url=http://www.oracle.com/technetwork/articles/piotrowski-pythoncore-084049.html |title=Build a Rapid Web Development Environment for Python Server Pages and Oracle |work=Oracle Technology Network |publisher=Oracle |date=July 2006 |access-date=12 March 2012 |archive-date=2 April 2019 |archive-url=https://web.archive.org/web/20190402124435/https://www.oracle.com/technetwork/articles/piotrowski-pythoncore-084049.html |url-status=live}}</ref>

<ref name="AutoNT-88">{{cite web |url=https://www.python.org/dev/peps/pep-0327/ |title=PEP 327&nbsp;– Decimal Data Type |last=Batista |first=Facundo |date=17 October 2003 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=24 November 2008 |archive-date=4 June 2020 |archive-url=https://web.archive.org/web/20200604234830/https://www.python.org/dev/peps/pep-0327/ |url-status=live}}</ref>

<ref name="AutoNT-89">{{cite web |url=https://www.python.org/dev/peps/pep-0333/ |title=PEP 333&nbsp;– Python Web Server Gateway Interface v1.0 |last=Eby |first=Phillip J. |date=7 December 2003 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=19 February 2012 |archive-date=14 June 2020 |archive-url=https://web.archive.org/web/20200614170344/https://www.python.org/dev/peps/pep-0333/ |url-status=live}}</ref>

<ref name="lj-bdfl-resignation">{{cite magazine |url=https://www.linuxjournal.com/content/guido-van-rossum-stepping-down-role-pythons-benevolent-dictator-life |title=Guido van Rossum Stepping Down from Role as Python's Benevolent Dictator For Life |last=Fairchild |first=Carlie |magazine=Linux Journal |date=12 July 2018 |access-date=13 July 2018 |archive-date=13 July 2018 |archive-url=https://web.archive.org/web/20180713192427/https://www.linuxjournal.com/content/guido-van-rossum-stepping-down-role-pythons-benevolent-dictator-life |url-status=live}}</ref>

}}

===Sources===
* {{cite web |url=https://wiki.python.org/moin/PythonForArtificialIntelligence |title=Python for Artificial Intelligence |publisher=Python Wiki |date=19 July 2012 |access-date=3 December 2012 |archive-url=https://web.archive.org/web/20121101045354/http://wiki.python.org/moin/PythonForArtificialIntelligence |archive-date=1 November 2012}}
* {{cite journal |editor-last=Paine |editor-first=Jocelyn |title=AI in Python |journal=AI Expert Newsletter |publisher=Amzi! |date=August 2005 |url=http://www.ainewsletter.com/newsletters/aix_0508.htm#python_ai_ai |access-date=11 February 2012 |archive-url=https://web.archive.org/web/20120326105810/http://www.ainewsletter.com/newsletters/aix_0508.htm#python_ai_ai |archive-date=26 March 2012 }}
* {{cite web |url=https://pypi.python.org/pypi/PyAIML |title=PyAIML 0.8.5: Python Package Index |publisher=Pypi.python.org |access-date=17 July 2013}}
* {{cite book |title=Artificial Intelligence: A Modern Approach |last1=Russell |first1=Stuart J. |author-link1=Stuart J. Russell |last2=Norvig |first2=Peter |author-link2=Peter Norvig |name-list-style=amp |edition=3rd |year=2009 |publisher=Prentice Hall |location=Upper Saddle River, NJ |isbn=978-0-13-604259-4}}

==Further reading==
<!-- THIS IS *NOT* A LIST OF ALL PYTHON BOOKS
According to [[Wikipedia:Further reading]], criteria for inclusion includes:
1. Should clearly qualify as WP:RS, as indicated by reviews and citations to it.
...
5. There should be guidelines on limiting the number of sources.
6. To avoid spam, any book included should have received more than one good review in RS: newspapers and scholarly journals being the norm, and the clear balance of RS reviews should be positive. This would avoid self-publish spamming, POV pushing, and attempts by publishers to get books promoted through inclusion on Wikipedia. At the moment "editorial recommendations" as described in the manual smacks of OR.
7. Neutrality on the part of editors is essential. In terms of major debates, items representing all major positions should be included, with annotations indicating the specific POV of each. We may have to work out rules where topic disputes are irreconcilable.
-->
* {{cite book |last=Downey |first=Allen |title=Think Python: How to Think Like a Computer Scientist |edition=3rd |date=July 2024 |publisher=O'Reilly Media |isbn=978-1-0981-5543-8 |url=https://allendowney.github.io/ThinkPython/}}
* {{cite book |last=Lutz |first=Mark |title=Learning Python |publisher=O'Reilly Media |year=2013 |edition=5th |isbn=978-0-596-15806-4}}
* {{cite book |last=Summerfield |first=Mark |title=Programming in Python 3 |publisher=Addison-Wesley Professional|year=2009|edition=2nd|isbn=978-0-321-68056-3}}
* {{cite book |last=Ramalho |first=Luciano |title=Fluent Python |url=https://www.thoughtworks.com/insights/books/fluent-python-2nd-edition |date=May 2022 |publisher=O'Reilly Media |isbn=978-1-4920-5632-4}}

==External links==
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{{Sister project links |wikt=no |display=Python |commons=Category:Python (programming language) |b=Python Programming |n=no |s=no |voy=no |species=no |d=Q28865}}
* {{Official website}}
* [https://docs.python.org/3/ Python documentation]
* [https://docs.python.org/3/tutorial/ The Python Tutorial]

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