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Python (programming language)

This page is about the programming language. For the snake, see python.

Python is a programming language. It was made to be open source and easy to read. A Dutch programmer named Guido van Rossum made Python in 1991. He named it after the television program Monty Python's Flying Circus. Many Python examples and tutorials include jokes from the show.[30]

Python (programming language)
Python-logo-notext.svg
Paradigm(s)Multi-paradigm: object-oriented,[1] procedural (imperative), functional, structured, reflective
Appeared in20 February 1991; 33 years ago (1991-02-20)[2]
Designed byGuido van Rossum
DeveloperPython Software Foundation
Typing disciplineDuck, dynamic, strong typing;[3] gradual (since 3.5, but ignored in CPython)[4]
Major implementationsCPython, PyPy, Stackless Python, MicroPython, CircuitPython, IronPython, Jython
DialectsCython, RPython, Starlark[5]
Influenced byABC,[6] Ada,[7] ALGOL 68,[8] APL,[9] C,[10] C++,[11] CLU,[12] Dylan,[13] Haskell,[14] Icon,[15] Java,[16] Lisp,[17] Modula-3,[11] Perl, Standard ML[9]
InfluencedApache Groovy, Boo, Cobra, CoffeeScript,[18] D, F#, Genie,[19] Go, JavaScript,[20][21] Julia,[22] Nim, Ring,[23] Ruby,[24] Swift,[25] V (Vlang)[26]
OSWindows, Linux/UNIX, macOS and more[27]
LicensePython Software Foundation License
Usual filename extensions.py, .pyi, .pyc, .pyd, .pyo (prior to 3.5),[28] .pyw, .pyz (since 3.5)[29]
Websitewww.python.org
Wikibooks logo Python Programming at Wikibooks

Python is an interpreted language. Interpreted languages do not need to be compiled to run. A program called an interpreter runs Python code on almost any kind of computer. This means that a programmer can change the code and quickly see the results. This also means Python is slower than a compiled language like C, because it is not turned into machine code ahead of time. Instead, this happens as the program is running.

Python's developers try to avoid changing the language to make it better until they have a lot of things to change. Also, they try not to make small repairs, called patches, to unimportant parts of CPython, the main version of Python, even if the patches would make it faster. When speed is important, a Python programmer can write some of the program in a different language, like C, or use PyPy, a different kind of Python that uses a just-in-time compiler.

Keeping Python fun to use is an important goal of Python’s developers. It reflects in the language's name, a tribute to the British comedy group Monty Python. Tutorials often take a playful approach, such as referring to spam and eggs instead of the standard foo and bar.

Python use

Python is usually used for making websites, automating common tasks, and making charts and graphs. Since it's simple to learn, people who are not computer experts, like bookkeepers and researchers, often learn Python.

Its standard library is made up of many functions that come with Python when it is installed.[31] On the Internet there are many other libraries libraries have been examined to provide wonderful ends in varied areas like Machine Learning (ML), Deep Learning, etc.[32] These libraries make it a powerful language; it can do many different things.

Syntax

Some of Python's syntax comes from C, because that is the language that Python was written in. But Python uses whitespace to delimit code: spaces or tabs are used to organize code into groups. This is different from C. In C, there is a semicolon at the end of each line and curly braces ({}) are used to group code. Using whitespace to delimit code makes Python a very easy-to-read language.[33]

Statements and control flow

Python's statements include:

  • The assignment statement, or the = sign. In Python, the statement x = 2 means that the name x is bound to the integer 2. Names can be rebound to many different types in Python, which is why Python is a dynamically typed language. For example, you could now type the statement x = 'spam' and it would work, but it wouldn't in another language like C or C++.
  • The if statement, which runs a block of code if certain conditions are met, along with else and elif (a contraction of else if from other programming languages). The elif statement runs a block of code if the previous conditions are not met, but the conditions for the elif statement are met. The else statement runs a block of code if none of the previous conditions are met.
  • The for statement, which iterates over an iterable object such as a list and binds each element of that object to a variable to use in that block of code, which creates a for loop.
  • The while statement, which runs a block of code as long as certain conditions are met, which creates a while loop.
  • The def statement, which defines a function or method.
  • The pass statement, which means "do nothing."
  • The class statement, which allows the user to create their own type of objects like what integers and strings are.
  • The import statement, which imports Python files for use in the user's code.
  • The print statement, which outputs various things to the console.

Expressions

Python's expressions include some that are similar to other programming languages and others that are not.

  • Addition, subtraction, multiplication, and division, represented by +, -. *, and /.
  • Exponents, represented by **.
  • To compare two values, Python uses ==.
  • Python uses the words "and", "or", and "not" for its boolean expressions.

Example

This is a small example of a Python program. It shows "Hello World!" on the screen.

<syntaxhighlight lang="python"> print("Hello World!")

  1. This code does the same thing, only it is longer:

ready = True if ready: 

   print("Hello World!")

</syntaxhighlight>

Python also does something called "dynamic variable assignment". This means that when a number or word is made in a program, the user does not have to say what type it is. This makes it easier to reuse variable names, making fast changes simpler. An example of this is shown below. This code will make both a number and a word, and show them both, using only one variable.

<syntaxhighlight lang="python"> x = 1 print(x) x = "Word" print(x) </syntaxhighlight>

In a "statically typed" language like C, a programmer would have to say whether x was a number or a word before C would let the programmer set up x, and after that, C would not allow its type to change from a number to a word.

Python (programming Language) Media

  • The designer of Python, Guido van Rossum, at OSCON 2006

  • An example of Python code and indentation

  • Example of C# code with curly braces and semicolons

  • The standard type hierarchy in Python 3

  • Python Powered:* * LSB * pandas * matplotlib * PyTorch*

References

  1. ↑ "General Python FAQ — Python 3.9.2 documentation". docs.python.org. Archived from the original on 24 October 2012. Retrieved 2021-03-28.
  2. ↑ "Python 0.9.1 part 01/21". alt.sources archives. Archived from the original on 11 August 2021. Retrieved 2021-08-11.
  3. ↑ "Why is Python a dynamic language and also a strongly typed language - Python Wiki". wiki.python.org. Archived from the original on 14 March 2021. Retrieved 2021-01-27.
  4. ↑ "PEP 483 -- The Theory of Type Hints". Python.org. Archived from the original on 14 June 2020. Retrieved 14 June 2018.
  5. ↑ "Starlark Language". Archived from the original on 15 June 2020. Retrieved 25 May 2019.
  6. ↑ "Why was Python created in the first place?". General Python FAQ. Python Software Foundation. Archived from the original on 24 October 2012. Retrieved 22 March 2007.
  7. ↑ "Ada 83 Reference Manual (raise statement)". Archived from the original on 22 October 2019. Retrieved 7 January 2020.
  8. ↑ Kuchling, Andrew M. (22 December 2006). "Interview with Guido van Rossum (July 1998)". amk.ca. Archived from the original on 1 May 2007. Retrieved 12 March 2012.
  9. ↑ 9.0 9.1 "itertools — Functions creating iterators for efficient looping — Python 3.7.1 documentation". docs.python.org. Archived from the original on 14 June 2020. Retrieved 22 November 2016.
  10. ↑ van Rossum, Guido (1993). "An Introduction to Python for UNIX/C Programmers". Proceedings of the NLUUG Najaarsconferentie (Dutch UNIX Users Group). CiteSeerX 10.1.1.38.2023. even though the design of C is far from ideal, its influence on Python is considerable.
  11. ↑ 11.0 11.1 "Classes". The Python Tutorial. Python Software Foundation. Archived from the original on 23 October 2012. Retrieved 20 February 2012. It is a mixture of the class mechanisms found in C++ and Modula-3
  12. ↑ Lundh, Fredrik. "Call By Object". effbot.org. Archived from the original on 23 November 2019. Retrieved 21 November 2017. 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.
  13. ↑ Simionato, Michele. "The Python 2.3 Method Resolution Order". Python Software Foundation. Archived from the original on 20 August 2020. Retrieved 29 July 2014. 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
  14. ↑ Kuchling, A. M. "Functional Programming HOWTO". Python v2.7.2 documentation. Python Software Foundation. Archived from the original on 24 October 2012. Retrieved 9 February 2012.
  15. ↑ Schemenauer, Neil; Peters, Tim; Hetland, Magnus Lie (18 May 2001). "PEP 255 – Simple Generators". Python Enhancement Proposals. Python Software Foundation. Archived from the original on 5 June 2020. Retrieved 9 February 2012.
  16. ↑ Smith, Kevin D.; Jewett, Jim J.; Montanaro, Skip; Baxter, Anthony (2 September 2004). "PEP 318 – Decorators for Functions and Methods". Python Enhancement Proposals. Python Software Foundation. Archived from the original on 3 June 2020. Retrieved 24 February 2012.
  17. ↑ "More Control Flow Tools". Python 3 documentation. Python Software Foundation. Archived from the original on 4 June 2016. Retrieved 24 July 2015.
  18. ↑ "CoffeeScript". coffeescript.org. Archived from the original on 12 June 2020. Retrieved 3 July 2018.
  19. ↑ "The Genie Programming Language Tutorial". Archived from the original on 1 June 2020. Retrieved 28 February 2020.
  20. ↑ "Perl and Python influences in JavaScript". www.2ality.com. 24 February 2013. Archived from the original on 26 December 2018. Retrieved 15 May 2015.
  21. ↑ Rauschmayer, Axel. "Chapter 3: The Nature of JavaScript; Influences". O'Reilly, Speaking JavaScript. Archived from the original on 26 December 2018. Retrieved 15 May 2015.
  22. ↑ "Why We Created Julia". Julia website. February 2012. Archived from the original on 2 May 2020. Retrieved 5 June 2014. We want something as usable for general programming as Python [...]
  23. ↑ Ring Team (4 December 2017). "Ring and other languages". ring-lang.net. ring-lang. Archived from the original on 25 December 2018. Retrieved 4 December 2017.
  24. ↑ Bini, Ola (2007). Practical JRuby on Rails Web 2.0 Projects: bringing Ruby on Rails to the Java platform. Berkeley: APress. p. 3. ISBN 978-1-59059-881-8.
  25. ↑ Lattner, Chris (3 June 2014). "Chris Lattner's Homepage". Chris Lattner. Archived from the original on 25 December 2018. Retrieved 3 June 2014. 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.
  26. ↑ "V Documentation". Retrieved 13 January 2024. its design has also been influenced by Oberon, Rust, Swift, Kotlin, and Python.
  27. ↑ "Download Python". Python.org. Archived from the original on 8 August 2018. Retrieved 2021-05-24.
  28. ↑ File extension .pyo was removed in Python 3.5. See PEP 0488 Archived 1 June 2020 at the Wayback Machine
  29. ↑ Holth, Moore (30 March 2014). "PEP 0441 -- Improving Python ZIP Application Support". Archived from the original on 26 December 2018. Retrieved 12 November 2015.
  30. ↑ "Python Humor". Python.org. Retrieved 2020-09-19.
  31. ↑ "Python Coding | Data Basecamp". 2021-11-27. Retrieved 2022-08-29.
  32. ↑ Yadav, Pramod (2020-10-09). "Top 25 Python Libraries For Data Science Projects – My Programming School". My Programming School. Retrieved 2022-12-22.
  33. ↑ Sah, Rocky (2022). "How Python parses white space". Codelivly - A Way For Coders. Archived from the original on 2022-12-14.

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