General Information¶
What is Python?¶
Python is an interpreted, interactive, object-oriented programming language. Itincorporates modules, exceptions, dynamic typing, very high level dynamic datatypes, and classes. It supports multiple programming paradigms beyondobject-oriented programming, such as procedural and functional programming.Python combines remarkable power with very clear syntax. It has interfaces tomany system calls and libraries, as well as to various window systems, and isextensible in C or C++. It is also usable as an extension language forapplications that need a programmable interface. Finally, Python is portable:it runs on many Unix variants including Linux and macOS, and on Windows.
To find out more, start with The Python Tutorial. The Beginner’s Guide toPython links to otherintroductory tutorials and resources for learning Python.
What is the Python Software Foundation?¶
The Python Software Foundation is an independent non-profit organization thatholds the copyright on Python versions 2.1 and newer. The PSF’s mission is toadvance open source technology related to the Python programming language and topublicize the use of Python. The PSF’s home page is athttps://www.python.org/psf/.
Donations to the PSF are tax-exempt in the US. If you use Python and find ithelpful, please contribute via the PSF donation page.
Are there copyright restrictions on the use of Python?¶
You can do anything you want with the source, as long as you leave thecopyrights in and display those copyrights in any documentation about Pythonthat you produce. If you honor the copyright rules, it’s OK to use Python forcommercial use, to sell copies of Python in source or binary form (modified orunmodified), or to sell products that incorporate Python in some form. We wouldstill like to know about all commercial use of Python, of course.
See the license page to find furtherexplanations and the full text of the PSF License.
The Python logo is trademarked, and in certain cases permission is required touse it. Consult the Trademark Usage Policy for more information.
Why was Python created in the first place?¶
Here’s a very brief summary of what started it all, written by Guido vanRossum:
I had extensive experience with implementing an interpreted language in theABC group at CWI, and from working with this group I had learned a lot aboutlanguage design. This is the origin of many Python features, including theuse of indentation for statement grouping and the inclusion ofvery-high-level data types (although the details are all different inPython).
I had a number of gripes about the ABC language, but also liked many of itsfeatures. It was impossible to extend the ABC language (or itsimplementation) to remedy my complaints – in fact its lack of extensibilitywas one of its biggest problems. I had some experience with using Modula-2+and talked with the designers of Modula-3 and read the Modula-3 report.Modula-3 is the origin of the syntax and semantics used for exceptions, andsome other Python features.
I was working in the Amoeba distributed operating system group at CWI. Weneeded a better way to do system administration than by writing either Cprograms or Bourne shell scripts, since Amoeba had its own system callinterface which wasn’t easily accessible from the Bourne shell. Myexperience with error handling in Amoeba made me acutely aware of theimportance of exceptions as a programming language feature.
It occurred to me that a scripting language with a syntax like ABC but withaccess to the Amoeba system calls would fill the need. I realized that itwould be foolish to write an Amoeba-specific language, so I decided that Ineeded a language that was generally extensible.
During the 1989 Christmas holidays, I had a lot of time on my hand, so Idecided to give it a try. During the next year, while still mostly workingon it in my own time, Python was used in the Amoeba project with increasingsuccess, and the feedback from colleagues made me add many earlyimprovements.
In February 1991, after just over a year of development, I decided to post toUSENET. The rest is in the
Misc/HISTORYfile.
What is Python good for?¶
Python is a high-level general-purpose programming language that can be appliedto many different classes of problems.
The language comes with a large standard library that covers areas such asstring processing (regular expressions, Unicode, calculating differences betweenfiles), internet protocols (HTTP, FTP, SMTP, XML-RPC, POP, IMAP),software engineering (unit testing, logging, profiling, parsingPython code), and operating system interfaces (system calls, filesystems, TCP/IPsockets). Look at the table of contents for The Python Standard Library to get an ideaof what’s available. A wide variety of third-party extensions are alsoavailable. Consult the Python Package Index tofind packages of interest to you.
How does the Python version numbering scheme work?¶
Python versions are numbered “A.B.C” or “A.B”:
A is the major version number – it is only incremented for really majorchanges in the language.
B is the minor version number – it is incremented for less earth-shatteringchanges.
C is the micro version number – it is incremented for each bugfix release.
Not all releases are bugfix releases. In the run-up to a new feature release, aseries of development releases are made, denoted as alpha, beta, or releasecandidate. Alphas are early releases in which interfaces aren’t yet finalized;it’s not unexpected to see an interface change between two alpha releases.Betas are more stable, preserving existing interfaces but possibly adding newmodules, and release candidates are frozen, making no changes except as neededto fix critical bugs.
Alpha, beta and release candidate versions have an additional suffix:
The suffix for an alpha version is “aN” for some small number N.
The suffix for a beta version is “bN” for some small number N.
The suffix for a release candidate version is “rcN” for some small number N.
In other words, all versions labeled 2.0aN precede the versions labeled2.0bN, which precede versions labeled 2.0rcN, and those precede 2.0.
You may also find version numbers with a “+” suffix, e.g. “2.2+”. These areunreleased versions, built directly from the CPython development repository. Inpractice, after a final minor release is made, the version is incremented to thenext minor version, which becomes the “a0” version, e.g. “2.4a0”.
See the Developer’s Guidefor more information about the development cycle, andPEP 387 to learn more about Python’s backward compatibility policy. See alsothe documentation for sys.version, sys.hexversion, andsys.version_info.
How do I obtain a copy of the Python source?¶
The latest Python source distribution is always available from python.org, athttps://www.python.org/downloads/. The latest development sources can be obtainedat https://github.com/python/cpython/.
The source distribution is a gzipped tar file containing the complete C source,Sphinx-formatted documentation, Python library modules, example programs, andseveral useful pieces of freely distributable software. The source will compileand run out of the box on most UNIX platforms.
Consult the Getting Started section of the Python Developer’s Guide for moreinformation on getting the source code and compiling it.
How do I get documentation on Python?¶
The standard documentation for the current stable version of Python is availableat https://docs.python.org/3/. PDF, plain text, and downloadable HTML versions arealso available at https://docs.python.org/3/download.html.
The documentation is written in reStructuredText and processed by the Sphinxdocumentation tool. The reStructuredText source forthe documentation is part of the Python source distribution.
I’ve never programmed before. Is there a Python tutorial?¶
There are numerous tutorials and books available. The standard documentationincludes The Python Tutorial.
Consult the Beginner’s Guide tofind information for beginning Python programmers, including lists of tutorials.
Is there a newsgroup or mailing list devoted to Python?¶
There is a newsgroup, comp.lang.python, and a mailing list,python-list. Thenewsgroup and mailing list are gatewayed into each other – if you can read newsit’s unnecessary to subscribe to the mailing list.comp.lang.python is high-traffic, receiving hundreds of postingsevery day, and Usenet readers are often more able to cope with this volume.
Announcements of new software releases and events can be found incomp.lang.python.announce, a low-traffic moderated list that receives about fivepostings per day. It’s available as the python-announce mailing list.
More info about other mailing lists and newsgroupscan be found at https://www.python.org/community/lists/.
How do I get a beta test version of Python?¶
Alpha and beta releases are available from https://www.python.org/downloads/. Allreleases are announced on the comp.lang.python and comp.lang.python.announcenewsgroups and on the Python home page at https://www.python.org/; an RSS feed ofnews is available.
You can also access the development version of Python through Git. SeeThe Python Developer’s Guide for details.
How do I submit bug reports and patches for Python?¶
To report a bug or submit a patch, use the issue tracker athttps://github.com/python/cpython/issues.
For more information on how Python is developed, consult the Python Developer’sGuide.
Are there any published articles about Python that I can reference?¶
It’s probably best to cite your favorite book about Python.
The very first article about Python waswritten in 1991 and is now quite outdated.
Guido van Rossum and Jelke de Boer, “Interactively Testing Remote ServersUsing the Python Programming Language”, CWI Quarterly, Volume 4, Issue 4(December 1991), Amsterdam, pp 283–303.
Are there any books on Python?¶
Yes, there are many, and more are being published. See the python.org wiki athttps://wiki.python.org/moin/PythonBooks for a list.
You can also search online bookstores for “Python” and filter out the MontyPython references; or perhaps search for “Python” and “language”.
Where in the world is www.python.org located?¶
The Python project’s infrastructure is located all over the world and is managedby the Python Infrastructure Team. Details here.
Why is it called Python?¶
When he began implementing Python, Guido van Rossum was also reading thepublished scripts from “Monty Python’s Flying Circus”, a BBC comedy series from the 1970s. Van Rossumthought he needed a name that was short, unique, and slightly mysterious, so hedecided to call the language Python.
Do I have to like “Monty Python’s Flying Circus”?¶
No, but it helps. :)
Python in the real world¶
How stable is Python?¶
Very stable. New, stable releases have been coming out roughly every 6 to 18months since 1991, and this seems likely to continue. As of version 3.9,Python will have a new feature release every 12 months (PEP 602).
The developers issue bugfix releases of older versions, so the stability ofexisting releases gradually improves. Bugfix releases, indicated by a thirdcomponent of the version number (e.g. 3.5.3, 3.6.2), are managed for stability;only fixes for known problems are included in a bugfix release, and it’sguaranteed that interfaces will remain the same throughout a series of bugfixreleases.
The latest stable releases can always be found on the Python download page. There are two production-ready versionsof Python: 2.x and 3.x. The recommended version is 3.x, which is supported bymost widely used libraries. Although 2.x is still widely used, it is notmaintained anymore.
How many people are using Python?¶
There are probably millions of users, though it’s difficult to obtain an exactcount.
Python is available for free download, so there are no sales figures, and it’savailable from many different sites and packaged with many Linux distributions,so download statistics don’t tell the whole story either.
The comp.lang.python newsgroup is very active, but not all Python users post tothe group or even read it.
Have any significant projects been done in Python?¶
See https://www.python.org/about/success for a list of projects that use Python.Consulting the proceedings for past Python conferences will reveal contributions from manydifferent companies and organizations.
High-profile Python projects include the Mailman mailing list manager and the Zope application server. Several Linux distributions, most notably Red Hat, have written part or all of their installer andsystem administration software in Python. Companies that use Python internallyinclude Google, Yahoo, and Lucasfilm Ltd.
What new developments are expected for Python in the future?¶
See https://peps.python.org/ for the Python Enhancement Proposals(PEPs). PEPs are design documents describing a suggested new feature for Python,providing a concise technical specification and a rationale. Look for a PEPtitled “Python X.Y Release Schedule”, where X.Y is a version that hasn’t beenpublicly released yet.
New development is discussed on the python-dev mailing list.
Is it reasonable to propose incompatible changes to Python?¶
In general, no. There are already millions of lines of Python code around theworld, so any change in the language that invalidates more than a very smallfraction of existing programs has to be frowned upon. Even if you can provide aconversion program, there’s still the problem of updating all documentation;many books have been written about Python, and we don’t want to invalidate themall at a single stroke.
Providing a gradual upgrade path is necessary if a feature has to be changed.PEP 5 describes the procedure followed for introducing backward-incompatiblechanges while minimizing disruption for users.
Is Python a good language for beginning programmers?¶
Yes.
It is still common to start students with a procedural and statically typedlanguage such as Pascal, C, or a subset of C++ or Java. Students may be betterserved by learning Python as their first language. Python has a very simple andconsistent syntax and a large standard library and, most importantly, usingPython in a beginning programming course lets students concentrate on importantprogramming skills such as problem decomposition and data type design. WithPython, students can be quickly introduced to basic concepts such as loops andprocedures. They can probably even work with user-defined objects in their veryfirst course.
For a student who has never programmed before, using a statically typed languageseems unnatural. It presents additional complexity that the student must masterand slows the pace of the course. The students are trying to learn to thinklike a computer, decompose problems, design consistent interfaces, andencapsulate data. While learning to use a statically typed language isimportant in the long term, it is not necessarily the best topic to address inthe students’ first programming course.
Many other aspects of Python make it a good first language. Like Java, Pythonhas a large standard library so that students can be assigned programmingprojects very early in the course that do something. Assignments aren’trestricted to the standard four-function calculator and check balancingprograms. By using the standard library, students can gain the satisfaction ofworking on realistic applications as they learn the fundamentals of programming.Using the standard library also teaches students about code reuse. Third-partymodules such as PyGame are also helpful in extending the students’ reach.
Python’s interactive interpreter enables students to test language featureswhile they’re programming. They can keep a window with the interpreter runningwhile they enter their program’s source in another window. If they can’tremember the methods for a list, they can do something like this:
>>> L = []>>> dir(L) ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__','__dir__', '__doc__', '__eq__', '__format__', '__ge__','__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__','__imul__', '__init__', '__iter__', '__le__', '__len__', '__lt__','__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__','__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__','__sizeof__', '__str__', '__subclasshook__', 'append', 'clear','copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove','reverse', 'sort']>>> [d for d in dir(L) if '__' not in d]['append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']>>> help(L.append)Help on built-in function append:append(...) L.append(object) -> None -- append object to end>>> L.append(1)>>> L[1]
With the interpreter, documentation is never far from the student as they areprogramming.
There are also good IDEs for Python. IDLE is a cross-platform IDE for Pythonthat is written in Python using Tkinter.Emacs users will be happy to know that there is a very good Python mode forEmacs. All of these programming environments provide syntax highlighting,auto-indenting, and access to the interactive interpreter while coding. Consultthe Python wiki for a full listof Python editing environments.
If you want to discuss Python’s use in education, you may be interested injoining the edu-sig mailing list.
