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Python is a high-level,
general-purpose programming language In computer software, a general-purpose programming language (GPL) is a programming language for building software in a wide variety of application Domain (software engineering), domains. Conversely, a domain-specific programming language is used w ...
. Its design philosophy emphasizes code readability with the use of significant indentation. Python is dynamically-typed and garbage-collected. It supports multiple
programming paradigm Programming paradigms are a way to classify programming languages based on their features. Languages can be classified into multiple paradigms. Some paradigms are concerned mainly with implications for the execution model of the language, suc ...
s, including structured (particularly procedural),
object-oriented Object-oriented programming (OOP) is a programming paradigm based on the concept of "Object (computer science), objects", which can contain data and Computer program, code. The data is in the form of Field (computer science), fields (often kno ...
and
functional programming In computer science Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied sc ...
. It is often described as a "batteries included" language due to its comprehensive
standard library In computer programming, a standard library is the library (computing), library made available across Programming language implementation, implementations of a programming language. These libraries are conventionally described in programming lang ...
. Guido van Rossum began working on Python in the late 1980s as a successor to the ABC programming language and first released it in 1991 as Python 0.9.0. Python 2.0 was released in 2000 and introduced new features such as
list comprehension A list comprehension is a Syntax of programming languages, syntactic construct available in some programming languages for creating a list based on existing list (computing), lists. It follows the form of the mathematical ''set-builder notation'' ( ...
s, cycle-detecting garbage collection, reference counting, and
Unicode Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, ...
support. Python 3.0, released in 2008, was a major revision that is not completely backward-compatible with earlier versions. Python 2 was discontinued with version 2.7.18 in 2020. Python consistently ranks as one of the most popular programming languages.


History

Python was conceived in the late 1980s by Guido van Rossum at Centrum Wiskunde & Informatica (CWI) in the
Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Neth ...
as a successor to the ABC programming language, which was inspired by SETL, capable of
exception handling In computing and computer programming, exception handling is the process of responding to the occurrence of ''exceptions'' – anomalous or exceptional conditions requiring special processing – during the Execution (computing), execution of a C ...
(from the start plus new capabilities in Python 3.11) and interfacing with the
Amoeba An amoeba (; less commonly spelled ameba or amœba; plural ''am(o)ebas'' or ''am(o)ebae'' ), often called an amoeboid, is a type of Cell (biology), cell or unicellular organism with the ability to alter its shape, primarily by extending and ret ...
operating system. Its implementation began in December 1989. Van Rossum shouldered sole responsibility for the project, as the lead developer, until 12 July 2018, when he announced his "permanent vacation" from his responsibilities as Python's " benevolent dictator for life", a title the Python community bestowed upon him to reflect his long-term commitment as the project's chief decision-maker. In January 2019, active Python core developers elected a five-member Steering Council to lead the project. Python 2.0 was released on 16 October 2000, with many major new features. Python 3.0, released on 3 December 2008, with many of its major features backported to Python 2.6.x and 2.7.x. Releases of Python 3 include the 2to3 utility, which automates the translation of Python 2 code to Python 3. Python 2.7's end-of-life was initially set for 2015, then postponed to 2020 out of concern that a large body of existing code could not easily be forward-ported to Python 3. No further security patches or other improvements will be released for it. Currently only 3.7 and later are supported. In 2021, Python 3.9.2 and 3.8.8 were expedited as all versions of Python (including 2.7) had security issues leading to possible
remote code execution In computer security, arbitrary code execution (ACE) is an attacker's ability to run any commands or code of the attacker's choice on a target machine or in a target Process (computing), process. An arbitrary code execution Vulnerability (computi ...
and web cache poisoning. In 2022, Python 3.10.4 and 3.9.12 were expedited and 3.8.13, and 3.7.13, because of many security issues. When Python 3.9.13 was released in May 2022, it was announced that the 3.9 series (joining the older series 3.8 and 3.7) will only receive security fixes going forward. On September 7, 2022, four new releases were made due to a potential
denial-of-service attack In computing, a denial-of-service attack (DoS attack) is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended user (computing), users by temporarily or indefinitely disrupting network ...
: 3.10.7, 3.9.14, 3.8.14, and 3.7.14. Python 3.11.0 is the current stable release and among the notable changes from 3.10 are that it is 10–60% faster and significantly improved error reporting. Python 3.12 (alpha 2) has improved error messages.


Removals from Python

The deprecated smtpd module has been removed from Python 3.12 (alpha). And a number of other old, broken and deprecated functions (e.g. from unittest module), classes and methods have been removed. The deprecated wstr and wstr_ length members of the C implementation of
Unicode Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, ...
objects were removed, to make
UTF-8 UTF-8 is a variable-length character encoding Character encoding is the process of assigning numbers to Graphics, graphical character (computing), characters, especially the written characters of Language, human language, allowing them to be ...
the default in later Python versions. Historically, Python 3 also made changes from Python 2, e.g. changed the division operator.


Design philosophy and features

Python is a
multi-paradigm programming language Programming paradigms are a way to classify programming languages based on their features. Languages can be classified into multiple paradigms. Some paradigms are concerned mainly with implications for the execution model of the language, suc ...
.
Object-oriented programming Object-oriented programming (OOP) is a programming paradigm based on the concept of " objects", which can contain data In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing qua ...
and
structured programming Structured programming is a programming paradigm Programming paradigms are a way to classify programming languages based on their features. Languages can be classified into multiple paradigms. Some paradigms are concerned mainly with impl ...
are fully supported, and many of their features support functional programming and aspect-oriented programming (including
metaprogramming Metaprogramming is a programming technique in which computer programs have the ability to treat other programs as their data. It means that a program can be designed to read, generate, analyze or transform other programs, and even modify itself ...
and metaobjects). Many other paradigms are supported via extensions, including design by contract and
logic programming Logic programming is a programming paradigm which is largely based on formal logic. Any program written in a logic programming language is a set of sentences in logical form, expressing facts and rules about some problem domain. Major logic prog ...
. Python uses
dynamic typing In computer programming, a type system is a logical system comprising a set of rules that assigns a property called a type (computer science), type to every "term" (a word, phrase, or other set of symbols). Usually the terms are various constru ...
and a combination of reference counting and a cycle-detecting garbage collector for
memory management Memory management is a form of Resource management (computing), resource management applied to computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their re ...
. It uses dynamic name resolution ( late binding), which binds method and variable names during program execution. Its design offers some support for functional programming in the
Lisp A lisp is a speech impairment in which a person misarticulates sibilants (, , , , , , , ). These misarticulations often result in unclear speech. Types * A frontal lisp occurs when the tongue is placed anterior to the target. Interdental lisping ...
tradition. It has functions;
list comprehension A list comprehension is a Syntax of programming languages, syntactic construct available in some programming languages for creating a list based on existing list (computing), lists. It follows the form of the mathematical ''set-builder notation'' ( ...
s,
dictionaries A dictionary is a listing of lexemes from the lexicon of one or more specific languages, often arranged Alphabetical order, alphabetically (or by radical-and-stroke sorting, radical and stroke for ideographic languages), which may include inf ...
, sets, and generator expressions. The standard library has two modules ( and ) that implement functional tools borrowed from
Haskell Haskell () is a General-purpose programming language, general-purpose, static typing, statically-typed, purely functional programming, purely functional programming language with type inference and lazy evaluation. Designed for teaching, resear ...
and
Standard ML Standard ML (SML) is a General-purpose programming language, general-purpose, Modular programming, modular, functional programming language with compile-time type checking and type inference. It is popular among compiler writers and programming l ...
. Its core philosophy is summarized in the document ''The Zen of Python'' (''PEP 20''), which includes
aphorism An aphorism (from Greek ἀφορισμός: ''aphorismos'', denoting 'delimitation', 'distinction', and 'definition') is a concise, terse, laconic, or memorable expression of a general truth or principle. Aphorisms are often handed down by ...
s such as: * Beautiful is better than ugly. * Explicit is better than implicit. * Simple is better than complex. * Complex is better than complicated. * Readability counts. Rather than building all of its 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 espoused the opposite approach. Python strives for a simpler, less-cluttered syntax and grammar while giving developers a choice in their coding methodology. In contrast to
Perl Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was offi ...
's " there is more than one way to do it" motto, Python embraces a "there should be one—and preferably only one—obvious way to do it" philosophy. Alex Martelli, a
Fellow A fellow is a concept whose exact meaning depends on context. In learned or professional A professional is a member of a profession or any person who works in a specified professional activity. The term also describes the standards of educ ...
at the Python Software Foundation and Python book author, wrote: "To describe something as 'clever' is ''not'' considered a compliment in the Python culture." Python's developers strive to avoid premature optimization and reject patches to non-critical parts of the
CPython CPython is the reference implementation of the Python (programming language), Python programming language. Written in C (programming language), C and Python, CPython is the default and most widely used implementation of the Python language. CP ...
reference implementation that would offer marginal increases in speed at the cost of clarity. When speed is important, a Python programmer can move time-critical functions to extension modules written in languages such as C; or use PyPy, a just-in-time compiler.
Cython Cython () is a programming language that aims to be a superset of the Python programming language, designed to give C (programming language), C-like performance with code that is written mostly in Python with optional additional C-inspired synt ...
is also available, which translates a Python script into C and makes direct C-level API calls into the Python interpreter. Python's developers aim for it to be fun to use. This is reflected in its name—a tribute to the British comedy group
Monty Python Monty Python (also collectively known as the Pythons) were a British comedy troupe who created the sketch comedy television show ''Monty Python's Flying Circus'', which first aired on the BBC in 1969. Forty-five episodes were made over four ...
—and in occasionally playful approaches to tutorials and reference materials, such as examples that refer to spam and eggs (a reference to a Monty Python sketch) instead of the standard foo, and bar. A common
neologism A neologism from Ancient Greek, Greek νέο- ''néo''(="new") and λόγος /''lógos'' meaning "speech, utterance"is a relatively recent or isolated term, word, or phrase that may be in the process of entering common use, but that has not ...
in the Python community is ''pythonic'', which has a wide range of meanings related to program style. "Pythonic" code may use Python idioms well, be natural or show fluency in the language, or conform with Python's minimalist philosophy and emphasis on readability. Code that is difficult to understand or reads like a rough transcription from another programming language is called ''unpythonic''. Python users and admirers, especially those considered knowledgeable or experienced, are often referred to as ''Pythonistas''.


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 brackets to delimit blocks, and semicolons after statements are allowed but rarely used. It has fewer syntactic exceptions and special cases than C or Pascal.


Indentation

Python uses whitespace indentation, rather than curly brackets or keywords, to delimit blocks. An increase in indentation comes after certain statements; a decrease in indentation signifies the end of the current block. Thus, the program's visual structure accurately represents its semantic structure. 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.


Statements and control flow

Python's
statements Statement or statements may refer to: Common uses *Statement (computer science), the smallest standalone element of an imperative programming language *Statement (logic), declarative sentence that is either true or false *Statement, a Sentence_(li ...
include: * The assignment statement, using a single equals sign = * The if statement, which conditionally executes a block of code, along with else and elif (a contraction of else-if) * The for statement, which iterates over an iterable object, capturing each element to a local variable for use by the attached block * The while statement, which executes a block of code as long as its condition is true * The try statement, which allows exceptions raised in its attached code block to be caught and handled by except clauses (or new syntax except* in Python 3.11 for exception groups); it also ensures that clean-up code in a finally block is always run regardless of how the block exits * The raise statement, used to raise a specified exception or re-raise a caught exception * The class statement, which executes a block of code and attaches its local namespace to a class, for use in object-oriented programming * The def statement, which defines a function or
method Method ( grc, μέθοδος, methodos) literally means a pursuit of knowledge, investigation, mode of prosecuting such inquiry, or system. In recent centuries it more often means a prescribed process for completing a task. It may refer to: *Scien ...
* The with statement, which encloses a code block within a context manager (for example, acquiring a lock before it is run, then releasing the lock; or opening and closing a file), allowing resource-acquisition-is-initialization (RAII)-like behavior and replacing a common try/finally idiom * The break statement, which exits a loop * The continue statement, which skips the rest of the current iteration and continues with the next * The del 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 * The pass statement, serving as a NOP, syntactically needed to create an empty code block * The assert statement, used in debugging to check for conditions that should apply * The yield statement, which returns a value from a generator function (and also an operator); used to implement
coroutine Coroutines are computer program A computer program is a sequence or set of instructions in a programming language for a computer to Execution (computing), execute. Computer programs are one component of software, which also includes software doc ...
s * The return statement, used to return a value from a function * The
import An import is the receiving country in an export from the sending country. Importation and exportation are the defining financial transactions of international trade. In international trade, the importation and exportation of goods are limited ...
statement, used to import modules whose functions or variables can be used in the current program The assignment statement (=) binds a name as a
reference Reference is a relationship between objects in which one object designates, or acts as a means by which to connect to or link to, another object. The first object in this relation is said to ''refer to'' the second object. It is called a ''name'' ...
to a separate, dynamically-allocated 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
data type In computer science and computer programming, a data type (or simply type) is a set of possible values and a set of allowed operations on it. A data type tells the compiler or Interpreter (computing), interpreter how the programmer intends to u ...
; however, it always refers to ''some'' object with a type. This is called
dynamic typing In computer programming, a type system is a logical system comprising a set of rules that assigns a property called a type (computer science), type to every "term" (a word, phrase, or other set of symbols). Usually the terms are various constru ...
—in contrast to statically-typed languages, where each variable may contain only a value of a certain type. Python does not support
tail call In computer science, a tail call is a subroutine call performed as the final action of a procedure. If the target of a tail is the same subroutine, the subroutine is said to be tail recursive, which is a special case of direct recursion (computer s ...
optimization or first-class continuations, and, according to Van Rossum, it never will. However, better support for
coroutine Coroutines are computer program A computer program is a sequence or set of instructions in a programming language for a computer to Execution (computing), execute. Computer programs are one component of software, which also includes software doc ...
-like functionality is provided by extending Python's generators. Before 2.5, generators were lazy
iterator In computer programming Computer programming is the process of performing a particular computation (or more generally, accomplishing a specific computing result), usually by designing and building an executable computer program. Programming in ...
s; data was passed unidirectionally out of the generator. From Python 2.5 on, it is possible to pass data back into a generator function; and from version 3.3, it can be passed through multiple stack levels.


Expressions

Python's expressions include: * The +, -, and * operators for mathematical addition, subtraction, and multiplication are similar to other languages, but the behavior of division differs. There are two types of divisions in Python: floor division (or integer division) // and floating-point/division. Python uses the ** operator for exponentiation. * Python uses the + operator for string concatenation. Python uses the * operator for duplicating a string a specified number of times. * The @ infix operator. It is intended to be used by libraries such as NumPy for
matrix multiplication In mathematics, particularly in linear algebra, matrix multiplication is a binary operation that produces a matrix (mathematics), matrix from two matrices. For matrix multiplication, the number of columns in the first matrix must be equal to the n ...
. * The syntax :=, called the "walrus operator", was introduced in Python 3.8. It assigns values to variables as part of a larger expression. * In Python,

compares by value. Python's is operator may be used to compare object identities (comparison by reference), and comparisons may be chained—for example, . * Python uses and, or, and not as boolean operators. * Python has a type of expression called a ''
list comprehension A list comprehension is a Syntax of programming languages, syntactic construct available in some programming languages for creating a list based on existing list (computing), lists. It follows the form of the mathematical ''set-builder notation'' ( ...
'', as well as a more general expression called a '' generator expression''. *
Anonymous function In computer programming Computer programming is the process of performing a particular computation (or more generally, accomplishing a specific computing result), usually by designing and building an executable computer program. Programming in ...
s are implemented using lambda expressions; however, there may be only one expression in each body. * Conditional expressions are written as (different in order of operands from the c ? x : y operator common to many other languages). * Python makes a distinction between lists and
tuple In mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in m ...
s. Lists are written as , are mutable, and cannot be used as the keys of dictionaries (dictionary keys must be immutable in Python). Tuples, written as , are immutable and thus can be used as keys of dictionaries, provided all of the tuple's elements are immutable. The + 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. Thus, given the variable t initially equal to , executing first evaluates , which yields , which is then assigned back to t—thereby effectively "modifying the contents" of t while conforming to the immutable nature of tuple objects. Parentheses are optional for tuples in unambiguous contexts. * Python features ''sequence unpacking'' where multiple expressions, each evaluating to anything that can be assigned (to a variable, writable property, etc.) are associated in an identical manner to that forming tuple literals—and, as a whole, are put on the left-hand side of the equal sign in an assignment statement. The statement expects an ''iterable'' object on the right-hand side of the equal sign that produces the same number of values as the provided writable expressions; when iterated through them, it assigns each of the produced values to the corresponding expression on the left. * Python has a "string format" operator % that functions analogously to printf format strings in C—e.g. evaluates to "spam=blah eggs=2". In Python 2.6+ and 3+, this was supplemented by the format() method of the str class, e.g. . Python 3.6 added "f-strings": . * Strings in Python can be concatenated by "adding" them (with the same operator as for adding integers and floats), e.g. returns "spameggs". If strings contain numbers, they are added as strings rather than integers, e.g. returns "22". * Python has various
string literal A string literal (computer programming), literal or anonymous string is a String (computer science), string value in the source code of a computer program. Modern Computer programming, programming languages commonly use a quoted sequence of charact ...
s: ** Delimited by single or double quote marks; unlike in
Unix shell A Unix shell is a command-line Interpreter (computing), interpreter or shell (computing), shell that provides a command line user interface for Unix-like operating systems. The shell is both an interactive command language and a scripting langua ...
s,
Perl Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was offi ...
, and Perl-influenced languages, single and double quote marks work the same. Both use the backslash (\) as an
escape character In computing and telecommunication, an escape character is a character (computing), character that invokes an alternative interpretation on the following characters in a character sequence. An escape character is a particular case of metacharac ...
. String interpolation became available in Python 3.6 as "formatted string literals". ** Triple-quoted (beginning and ending with three single or double quote marks), which may span multiple lines and function like here documents in shells, Perl, and
Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapp ...
. ** Raw string varieties, denoted by prefixing the string literal with r. Escape sequences are not interpreted; hence raw strings are useful where literal backslashes are common, such as
regular expression A regular expression (shortened as regex or regexp; sometimes referred to as rational expression) is a sequence of Character (computing), characters that specifies a pattern matching, search pattern in String (computer science), text. Usually s ...
s and
Windows Windows is a group of several Proprietary software, proprietary graphical user interface, graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, W ...
-style paths. (Compare "@-quoting" in C#.) * Python has array index and array slicing expressions in lists, denoted as a ey/code>, or . Indexes are 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 third slice parameter called ''step'' or ''stride'', allows elements to be skipped and reversed. Slice indexes may be omitted—for example, 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 Common Lisp (CL) is a dialect of the Lisp programming language, published in ANSI standard document ''ANSI INCITS 226-1994 (S20018)'' (formerly ''X3.226-1994 (R1999)''). The Common Lisp HyperSpec, a hyperlinked HTML version, has been derived ...
, Scheme, or
Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapp ...
. This leads to duplicating some functionality. For example: * List comprehensions vs. for-loops * Conditional expressions vs. if blocks * The eval() vs. exec() built-in functions (in Python 2, exec is a statement); the former is for expressions, the latter is for statements Statements cannot be a part of an expression—so list and other comprehensions or lambda expressions, all being expressions, cannot contain statements. A particular case is that an assignment statement such as cannot form part of the conditional expression of a conditional statement. This has the advantage of avoiding a classic C error of mistaking an assignment operator = for an equality operator

in conditions: is syntactically valid (but probably unintended) C code, but causes a syntax error in Python.


Methods

Methods Method ( grc, μέθοδος, methodos) literally means a pursuit of knowledge, investigation, mode of prosecuting such inquiry, or system. In recent centuries it more often means a prescribed process for completing a task. It may refer to: *Scien ...
on objects are functions attached to the object's class; the syntax is, for normal methods and functions, syntactic sugar for . Python methods have an explicit
self The self is an individual as the object of that individual’s own reflective consciousness. Since the ''self'' is a reference by a subject to the same subject, this reference is necessarily Subjective character of experience, subjective. The sen ...
parameter to access instance data, in contrast to the implicit self (or this) in some other object-oriented programming languages (e.g., C++, Java,
Objective-C Objective-C is a General-purpose programming language, general-purpose, Object-oriented programming, object-oriented programming language that adds Smalltalk-style Message passing, messaging to the C (programming language), C programming languag ...
,
Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapp ...
). Python also provides methods, often called ''dunder methods'' (due to their names beginning and ending with double-underscores), to allow user-defined classes to modify how they are handled by native operations including length, comparison, in
arithmetic operations Arithmetic () is an elementary part of mathematics that consists of the study of the properties of the traditional operation (mathematics), operations on numbers—addition, subtraction, multiplication, division (mathematics), division, exponent ...
and type conversion.


Typing

Python uses duck typing and has typed objects but untyped variable names. Type constraints are not checked at
compile time In computer science, compile time (or compile-time) describes the time window during which a computer program is compiled. The term is used as an adjective to describe concepts related to the context of program compilation, as opposed to concept ...
; rather, operations on an object may fail, signifying that it is not of a suitable type. Despite being dynamically typed, Python is strongly typed, forbidding operations that are not well-defined (for example, adding a number to a string) rather than silently attempting to make sense of them. Python allows programmers to define their own types using classes, most often used for
object-oriented programming Object-oriented programming (OOP) is a programming paradigm based on the concept of " objects", which can contain data In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing qua ...
. New instances of classes are constructed by calling the class (for example, or ), and the classes are instances of the
metaclass In object-oriented programming, a metaclass is a Class (computer science), class whose instances are classes. Just as an ordinary class defines the behavior of certain objects, a metaclass defines the behavior of certain classes and their instanc ...
type (itself an instance of itself), allowing metaprogramming and reflection. Before version 3.0, Python had two kinds of classes (both using the same syntax): ''old-style'' and ''new-style'', current Python versions only support the semantics new style. The long-term plan is to support gradual typing. Python's syntax allows specifying static types, but they are not checked in the default implementation,
CPython CPython is the reference implementation of the Python (programming language), Python programming language. Written in C (programming language), C and Python, CPython is the default and most widely used implementation of the Python language. CP ...
. An experimental optional static type-checker, ''mypy'', supports compile-time type checking.


Arithmetic operations

Python has the usual symbols for arithmetic operators (+, -, *, /), the floor division operator // and the
modulo operation In computing, the modulo operation returns the remainder or signed remainder of a division, after one number is divided by another (called the '' modulus'' of the operation). Given two positive numbers and , modulo (often abbreviated as ) is ...
% (where the remainder can be negative, e.g. 4 % -3

-2
). It also has ** for
exponentiation Exponentiation is a mathematics, mathematical operation (mathematics), operation, written as , involving two numbers, the ''Base (exponentiation), base'' and the ''exponent'' or ''power'' , and pronounced as " (raised) to the (power of) ". W ...
, e.g. 5**3

125
and 9**0.5

3.0
, and a matrix‑multiplication operator @ . These operators work like in traditional math; with the same precedence rules, the operators
infix An infix is an affix inserted inside a word stem (an existing word or the core of a family of words). It contrasts with ''adfix,'' a rare term for an affix attached to the outside of a stem, such as a prefix or suffix. When marking text for int ...
(+ and - can also be unary to represent positive and negative numbers respectively). The division between integers produces floating-point results. The behavior of division has changed significantly over time: * Current Python (i.e. since 3.0) changed / to always be floating-point division, e.g. . * The floor division // operator was introduced. So 7//3

2
, -7//3

-3
, 7.5//3

2.0
and -7.5//3

-3.0
. Adding causes a module used in Python 2.7 to use Python 3.0 rules for division (see above). In Python terms, / is ''true division'' (or simply ''division''), and // is ''floor division.'' / before version 3.0 is ''classic division''. Rounding towards negative infinity, though different from most languages, adds consistency. For instance, it means that the equation is always true. It also means that the equation is valid for both positive and negative values of a. However, maintaining the validity of this equation means that while the result of a%b is, as expected, in the half-open interval , ''b''), where b is a positive integer, it has to lie in the interval (''b'', 0when b is negative. Python provides a round function for
rounding Rounding means replacing a number with an approximation, approximate value that has a shorter, simpler, or more explicit representation. For example, replacing $ with $, the fraction 312/937 with 1/3, or the expression with . Rounding is oft ...
a float to the nearest integer. For tie-breaking, Python 3 uses round to even: round(1.5) and round(2.5) both produce 2. Versions before 3 used round-away-from-zero: round(0.5) is 1.0, round(-0.5) is −1.0. Python allows boolean expressions with multiple equality relations in a manner that is consistent with general use in mathematics. For example, the expression a < b < c tests whether a is less than b and b is less than c. C-derived languages interpret this expression differently: in C, the expression would first evaluate a < b, resulting in 0 or 1, and that result would then be compared with c. Python uses arbitrary-precision arithmetic for all integer operations. The Decimal type/class in the decimal module provides decimal floating-point numbers to a pre-defined arbitrary precision and several rounding modes. The Fraction class in the fractions module provides arbitrary precision for
rational number In mathematics, a rational number is a number that can be expressed as the quotient or fraction (mathematics), fraction of two integers, a numerator and a non-zero denominator . For example, is a rational number, as is every integer (e.g. ) ...
s. Due to Python's extensive mathematics library, and the third-party library NumPy that further extends the native capabilities, it is frequently used as a scientific scripting language to aid in problems such as numerical data processing and manipulation.


Programming examples

Hello world program: print('Hello, world!') Program to calculate the
factorial In mathematics, the factorial of a non-negative denoted is the Product (mathematics), product of all positive integers less than or equal The factorial also equals the product of n with the next smaller factorial: \begin n! &= n \times ...
of a positive integer: n = int(input('Type a number, and its factorial will be printed: ')) 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)


Libraries

Python's large standard library provides tools suited to many tasks and is commonly cited as one of its greatest strengths. For Internet-facing applications, many standard formats and protocols such as
MIME Multipurpose Internet Mail Extensions (MIME) is an Internet standard that extends the format of email Electronic mail (email or e-mail) is a method of exchanging messages ("mail") between people using electronic devices. Email was th ...
and
HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, w ...
are supported. It includes modules for creating
graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows User (computing), users to Human–computer interaction, interact with electronic devices through graphical icon (comp ...
s, connecting to
relational database A relational database is a (most commonly digital) database based on the relational model of data, as proposed by E. F. Codd in 1970. A system used to maintain relational databases is a relational database management system (RDBMS). Many relation ...
s, generating pseudorandom numbers, arithmetic with arbitrary-precision decimals, manipulating
regular expression A regular expression (shortened as regex or regexp; sometimes referred to as rational expression) is a sequence of Character (computing), characters that specifies a pattern matching, search pattern in String (computer science), text. Usually s ...
s, and
unit testing In computer programming, unit testing is a software testing method by which individual units of source code—sets of one or more computer program Modular programming, modules together with associated control data, usage Procedure (computer ...
. Some parts of the standard library are covered by specifications—for example, the
Web Server Gateway Interface The Web Server Gateway Interface (WSGI, pronounced ''whiskey'' or ) is a simple calling convention for web server A web server is computer software and underlying Computer hardware, hardware that accepts requests via Hypertext Transf ...
(WSGI) implementation wsgiref follows PEP 333—but most are specified by their code, internal documentation, and test suites. However, because most of the standard library is cross-platform Python code, only a few modules need altering or rewriting for variant implementations. the Python Package Index (PyPI), the official repository for third-party Python software, contains over 415,000 packages with a wide range of functionality, including:


Development environments

Most Python implementations (including CPython) include a
read–eval–print loop A read–eval–print loop (REPL), also termed an interactive toplevel or language shell, is a simple interactive computer programming environment that takes single user inputs, executes them, and returns the result to the user; a program written ...
(REPL), permitting them to function as a command line interpreter for which users enter statements sequentially and receive results immediately. Python also comes with an Integrated development environment (IDE) called IDLE, which is more beginner-oriented. Other shells, including IDLE and IPython, add further abilities such as improved auto-completion, session state retention, and
syntax highlighting Syntax highlighting is a feature of text editors that are used for programming language, programming, scripting language, scripting, or markup language, markup languages, such as HTML. The feature displays text, especially source code, in differ ...
. As well as standard desktop
integrated development environment An integrated development environment (IDE) is a Application software, software application that provides comprehensive facilities to computer programmers for software development. An IDE normally consists of at least a source code editor, build ...
s, there are
Web browser A web browser is application software for accessing websites. When a User (computing), user requests a web page from a particular website, the browser retrieves its Computer file, files from a web server and then displays the page on the user' ...
-based IDEs, including
SageMath SageMath (previously Sage or SAGE, "System for Algebra and Geometry Experimentation") is a computer algebra system (CAS) with features covering many aspects of mathematics, including algebra, combinatorics, graph theory, numerical analysis, numbe ...
, for developing science- and math-related programs; PythonAnywhere, a browser-based IDE and hosting environment; and Canopy IDE, a commercial IDE emphasizing
scientific computing Computational science, also known as scientific computing or scientific computation (SC), is a field in mathematics that uses advanced computing capabilities to understand and solve complex problems. It is an area of science that spans many disc ...
.


Implementations


Reference implementation

CPython CPython is the reference implementation of the Python (programming language), Python programming language. Written in C (programming language), C and Python, CPython is the default and most widely used implementation of the Python language. CP ...
is the reference implementation of Python. It is written in C, meeting the C89 standard (Python 3.11 uses C11) with several select C99 features (With later C versions out, it is considered outdated. CPython includes its own C extensions, but third-party extensions are not limited to older C versions—e.g. they can be implemented with C11 or C++.) It compiles Python programs into an intermediate
bytecode Bytecode (also called portable code or p-code) is a form of instruction set designed for efficient execution by a software Interpreter (computing), interpreter. Unlike Human-readable code, human-readable source code, bytecodes are compact nume ...
which is then executed by its
virtual machine In computing, a virtual machine (VM) is the virtualization/emulator, emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve special ...
. CPython is distributed with a large standard library written in a mixture of C and native Python, and is available for many platforms, including Windows (starting with Python 3.9, the Python installer deliberately fails to install on
Windows 7 Windows 7 is a major release of the Windows NT operating system developed by Microsoft. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on July 22, 2009, and became generally available on October 22, ...
and 8;
Windows XP Windows XP is a major release of Microsoft's Windows NT operating system. It was release to manufacturing, released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct upgrade to its predecessors, Wind ...
was supported until Python 3.5) and most modern
Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix- ...
systems, including macOS (and Apple M1 Macs, since Python 3.9.1, with experimental installer) and unofficial support for e.g. VMS. Platform portability was one of its earliest priorities. (During Python 1 and 2 development, even
OS/2 OS/2 (Operating System/2) is a series of computer operating systems, initially created by Microsoft and IBM under the leadership of IBM software designer Ed Iacobucci. As a result of a feud between the two companies over how to position OS/2 re ...
and Solaris were supported, but support has since been dropped for many platforms.)


Other implementations

* PyPy is a fast, compliant interpreter of Python 2.7 and 3.8. Its just-in-time compiler often brings a significant speed improvement over CPython but some libraries written in C cannot be used with it. * Stackless Python is a significant fork of CPython that implements microthreads; it does not use the
call stack In computer science, a call stack is a Stack (abstract data type), stack data structure that stores information about the active subroutines of a computer program. This kind of stack is also known as an execution stack, program stack, control st ...
in the same way, thus allowing massively concurrent programs. PyPy also has a stackless version. *
MicroPython MicroPython is a software Software is a set of computer programs and associated software documentation, documentation and data (computing), data. This is in contrast to Computer hardware, hardware, from which the system is built and which ...
and
CircuitPython CircuitPython is an open-source derivative of the MicroPython programming language targeted toward students and beginners. Development of CircuitPython is supported by Adafruit Industries. It is a software implementation of the Python (programming ...
are Python 3 variants optimized for
microcontroller A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more Central processing unit, CPUs (processor cores) along with ...
s, including
Lego Mindstorms EV3 LEGO Mindstorms EV3 is the third generation robotics kit in Lego, LEGO's Lego Mindstorms, Mindstorms line. It is the successor to the second generation Lego Mindstorms NXT, LEGO Mindstorms NXT kit. The "EV" designation refers to the "evolution" of ...
. * Pyston is a variant of the Python runtime that uses just-in-time compilation to speed up the execution of Python programs. * Cinder is a performance-oriented fork of CPython 3.8 that contains a number of optimizations including bytecode inline caching, eager evaluation of coroutines, a method-at-a-time JIT, and an experimental bytecode compiler.


Unsupported implementations

Other just-in-time Python compilers have been developed, but are now unsupported: * Google began a project named Unladen Swallow in 2009, with the aim of speeding up the Python interpreter fivefold by using the
LLVM LLVM is a set of compiler and toolchain technologies that can be used to develop a front end for any programming language and a back end for any instruction set architecture. LLVM is designed around a language-independent intermediate rep ...
, and of improving its multithreading ability to scale to thousands of cores, while ordinary implementations suffer from the global interpreter lock. * Psyco is a discontinued just-in-time specializing compiler that integrates with CPython and transforms bytecode to machine code at runtime. The emitted code is specialized for certain
data type In computer science and computer programming, a data type (or simply type) is a set of possible values and a set of allowed operations on it. A data type tells the compiler or Interpreter (computing), interpreter how the programmer intends to u ...
s and is faster than the standard Python code. Psyco does not support Python 2.7 or later. * PyS60 was a Python 2 interpreter for Series 60 mobile phones released by
Nokia Nokia Corporation (natively Nokia Oyj, referred to as Nokia) is a Finnish multinational corporation, multinational telecommunications industry, telecommunications, technology company, information technology, and consumer electronics corporatio ...
in 2005. It implemented many of the modules from the standard library and some additional modules for integrating with the
Symbian Symbian is a discontinued mobile operating system (OS) and computing platform designed for smartphones. It was originally developed as a proprietary software OS for personal digital assistants in 1998 by the Symbian Ltd. consortium. Symbian OS ...
operating system. The Nokia N900 also supports Python with
GTK GTK (formerly GIMP ToolKit and GTK+) is a free and open-source cross-platform widget toolkit for creating graphical user interfaces (GUIs). It is licensed under the terms of the GNU Lesser General Public License, allowing both Free software, fre ...
widget libraries, enabling programs to be written and run on the target device.


Cross-compilers to other languages

There are several compilers to high-level object languages, with either unrestricted Python, a restricted subset of Python, or a language similar to Python as the source language: * Brython, Transcrypt and Pyjs (latest release in 2012) compile Python to
JavaScript JavaScript (), often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web The World Wide Web (WWW), commonly known as the Web, is an information system enabling documents and oth ...
. *
Cython Cython () is a programming language that aims to be a superset of the Python programming language, designed to give C (programming language), C-like performance with code that is written mostly in Python with optional additional C-inspired synt ...
compiles (a superset of) Python 2.7 to C (while the resulting code is also usable with Python 3 and also e.g. C++). * Nuitka compiles Python into C. * Numba uses LLVM to compile a subset of Python to machine code. * Pythran compiles a subset of Python 3 to C++ (
C++11 C++11 is a version of the International Organization for Standardization, ISO/International Electrotechnical Commission, IEC 14882 standard for the C++ programming language. C++11 replaced the prior version of the C++ standard, called C++03, and ...
). * RPython can be compiled to C, and is used to build the PyPy interpreter of Python. * The Python → 11l → C++ transpiler compiles a subset of Python 3 to C++ ( C++17). Specialized: * MyHDL is a Python-based hardware description language (HDL), that converts MyHDL code to Verilog or VHDL code. Older projects (or not to be used with Python 3.x and latest syntax): * Google's Grumpy (latest release in 2017) transpiles Python 2 to Go. * IronPython allows running Python 2.7 programs (and an
alpha Alpha (uppercase , lowercase ; grc, ἄλφα, ', or ell, άλφα, álfa) is the first Letter (alphabet), letter of the Greek alphabet. In the system of Greek numerals, it has a value of one. Alpha is derived from the Phoenician alphabet, P ...
, released in 2021, is also available for "Python 3.4, although features and behaviors from later versions may be included") on the .NET
Common Language Runtime The Common Language Runtime (CLR), the virtual machine component of Microsoft .NET Framework, manages the execution of .NET programs. Just-in-time compilation converts the managed code (compiled intermediate language code) into machine instructio ...
. *
Jython Jython is an implementation of the Python (programming language), Python programming language designed to run on the Java (programming language), Java platform. The implementation was formerly known as JPython until 1999. Overview Jython progra ...
compiles Python 2.7 to Java bytecode, allowing the use of the Java libraries from a Python program. *
Pyrex Pyrex (trademarked as ''PYREX'' and ''pyrex'') is a brand introduced by Corning Inc. in 1915 for a line of clear, low-thermal-expansion borosilicate glass used for laboratory glassware and kitchenware. It was later expanded to include kitchenwa ...
(latest release in 2010) and Shed Skin (latest release in 2013) compile to C and C++ respectively.


Performance

Performance comparison of various Python implementations on a non-numerical (combinatorial) workload was presented at EuroSciPy '13. Python's performance compared to other programming languages is also benchmarked by The Computer Language Benchmarks Game.


Development

Python's development is conducted largely through the ''Python Enhancement Proposal'' (PEP) process, the primary mechanism for proposing major new features, collecting community input on issues, and documenting Python design decisions. Python coding style is covered in PEP 8. Outstanding PEPs are reviewed and commented on by the Python community and the steering council. Enhancement of the language corresponds with the 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 bug tracker hosted at by the foundation. In 2022, all issues and discussions were migrated to
GitHub GitHub, Inc. () is an Internet hosting service for software development and version control using Git. It provides the distributed version control of Git plus access control, bug tracking system, bug tracking, software feature requests, task man ...
. Development originally took place on a self-hosted source-code repository running Mercurial, until Python moved to
GitHub GitHub, Inc. () is an Internet hosting service for software development and version control using Git. It provides the distributed version control of Git plus access control, bug tracking system, bug tracking, software feature requests, task man ...
in January 2017. CPython's public releases come in three types, distinguished by which part of the version number is incremented: * Backward-incompatible versions, where code is expected to break and needs to 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 is very unlikely to ever happen. * 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 3.9, these releases are expected to happen annually. Each major version is supported by bug fixes for several years after its release. * Bugfix releases, which introduce no new features, occur about every 3 months and are made when a sufficient number of bugs have been fixed upstream since the last release. Security vulnerabilities are also patched in these releases. The third and final part of the version number is incremented. Many alpha, beta, and release-candidates are also released as previews and for testing before final releases. Although there is a rough schedule for each release, they are often delayed if the code is not ready. Python's development team monitors the state of the code by running the large unit test suite during development. The major
academic conference An academic conference or scientific conference (also congress, symposium, workshop, or meeting) is an Convention (meeting), event for researchers (not necessarily academics) to present and discuss their scholarly work. Together with academic jou ...
on Python is PyCon. There are also special Python mentoring programs, such as Pyladies. Python 3.10 deprecated wstr (to be removed in Python 3.12; meaning Python extensions need to be modified by then), and added
pattern matching In computer science, pattern matching is the act of checking a given sequence of Lexical analysis#Token, tokens for the presence of the constituents of some pattern. In contrast to pattern recognition, the match usually has to be exact: "either ...
to the language.


API documentation generators

Tools that can generate documentation for Python API include pydoc (available as part of the standard library),
Sphinx A sphinx ( , grc, σφίγξ , Aeolic Greek, Boeotian: , plural sphinxes or sphinges) is a mythical creature with the head of a human, the body of a lion, and the wings of a falcon. In Culture of Greece, Greek tradition, the sphinx has the he ...
, Pdoc and its forks, Doxygen and Graphviz, among others.


Naming

Python's name is derived from the British comedy group
Monty Python Monty Python (also collectively known as the Pythons) were a British comedy troupe who created the sketch comedy television show ''Monty Python's Flying Circus'', which first aired on the BBC in 1969. Forty-five episodes were made over four ...
, whom Python creator Guido van Rossum enjoyed while developing the language. Monty Python references appear frequently in Python code and culture; for example, the metasyntactic variables often used in Python literature are ''spam'' and ''eggs'' instead of the traditional ''foo'' and ''bar''. The official Python documentation also contains various references to Monty Python routines. The prefix ''Py-'' is used to show that something is related to Python. Examples of the use of this prefix in names of Python applications or libraries include Pygame, a binding of SDL to Python (commonly used to create games); PyQt and PyGTK, which bind Qt and GTK to Python respectively; and PyPy, a Python implementation originally written in Python.


Popularity

Since 2003, Python has consistently ranked in the top ten most popular programming languages in the TIOBE Programming Community Index where, , it is the most popular language (ahead of
Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...
, and C). It was selected Programming Language of the Year (for "the highest rise in ratings in a year") in 2007, 2010, 2018, and 2020 (the only language to do so four times). An empirical study found that scripting languages, such as Python, are more productive than conventional languages, such as C and Java, for programming problems involving string manipulation and search in a dictionary, and determined that memory consumption was often "better than Java and not much worse than C or C++". Large organizations that use Python include
Wikipedia Wikipedia is a multilingual Multilingualism is the use of more than one language, either by an individual speaker or by a group of speakers. It is believed that multilingual speakers outnumber monolingual speakers in the world's ...
,
Google Google LLC () is an American Multinational corporation, multinational technology company focusing on Search Engine, search engine technology, online advertising, cloud computing, software, computer software, quantum computing, e-commerce, ar ...
,
Yahoo! Yahoo! (, styled yahoo''!'' in its logo) is an American web services provider. It is headquartered in Sunnyvale, California and operated by the namesake company Yahoo Inc., which is 90% owned by investment funds managed by Apollo Global M ...
,
CERN The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in a northwestern suburb of Gene ...
,
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...
,
Facebook Facebook is an online social media and social networking service owned by American company Meta Platforms. Founded in 2004 by Mark Zuckerberg with fellow Harvard College students and roommates Eduardo Saverin, Andrew McCollum, Dusti ...
,
Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technology co ...
,
Instagram Instagram is a photo and video sharing social networking service owned by American company Meta Platforms. The app allows users to upload media that can be edited with Social media camera filter, filters and organized by hashtags and Geotaggi ...
,
Spotify Spotify (; ) is a proprietary software, proprietary Swedish Streaming media, audio streaming and media services provider founded on 23 April 2006 by Daniel Ek and Martin Lorentzon. It is one of the largest music streaming service providers, with ...
, and some smaller entities like ILM and ITA. The social news networking site
Reddit Reddit (; stylized in all lowercase as reddit) is an American social news news aggregator, aggregation, Review site#Rating site, content rating, and Internet forum, discussion website. Registered users (commonly referred to as "Redditors") subm ...
was written mostly in Python.


Uses

Python can serve as a
scripting language A scripting language or script language is a programming language that is used to manipulate, customize, and automate the facilities of an existing system. Scripting languages are usually Interpreter (computing), interpreted at Runtime (program li ...
for
web application A web application (or web app) is application software that is accessed using a web browser. Web applications are delivered on the World Wide Web to users with an active network connection. History In earlier computing models like client-serve ...
s, e.g., via for the Apache webserver. With
Web Server Gateway Interface The Web Server Gateway Interface (WSGI, pronounced ''whiskey'' or ) is a simple calling convention for web server A web server is computer software and underlying Computer hardware, hardware that accepts requests via Hypertext Transf ...
, a standard API has evolved to facilitate these applications. Web frameworks like Django, Pylons,
Pyramid A pyramid (from el, πυραμίς ') is a Nonbuilding structure, structure whose outer surfaces are triangular and converge to a single step at the top, making the shape roughly a Pyramid (geometry), pyramid in the geometric sense. The base o ...
, TurboGears, web2py,
Tornado A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, althou ...
, Flask, Bottle, and Zope support developers in the design and maintenance of complex applications. Pyjs and IronPython can be used to develop the client-side of Ajax-based applications. SQLAlchemy can be used as a data mapper to a relational database. Twisted is a framework to program communications between computers, and is used (for example) by Dropbox. Libraries such as NumPy, SciPy, and Matplotlib allow the effective use of Python in scientific computing, with specialized libraries such as Biopython and Astropy providing domain-specific functionality.
SageMath SageMath (previously Sage or SAGE, "System for Algebra and Geometry Experimentation") is a computer algebra system (CAS) with features covering many aspects of mathematics, including algebra, combinatorics, graph theory, numerical analysis, numbe ...
is a
computer algebra system A computer algebra system (CAS) or symbolic algebra system (SAS) is any mathematical software with the ability to manipulate mathematical expressions in a way similar to the traditional manual computations of mathematicians and scientists. The de ...
with a
notebook interface A notebook interface (also called a computational notebook) is a virtual notebook environment used for literate programming, a method of writing computer programs. Some notebooks are WYSIWYG environments including executable calculations embedded i ...
programmable in Python: its library covers many aspects of
mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...
, including
algebra Algebra () is one of the areas of mathematics, broad areas of mathematics. Roughly speaking, algebra is the study of mathematical symbols and the rules for manipulating these symbols in formulas; it is a unifying thread of almost all of mathem ...
,
combinatorics Combinatorics is an area of mathematics primarily concerned with counting, both as a means and an end in obtaining results, and certain properties of finite set, finite Mathematical structure, structures. It is closely related to many other ar ...
, numerical mathematics,
number theory Number theory (or arithmetic or higher arithmetic in older usage) is a branch of pure mathematics devoted primarily to the study of the integer An integer is the number zero (), a positive natural number (, , , etc.) or a negative intege ...
, and
calculus Calculus, originally called infinitesimal calculus or "the calculus of infinitesimals", is the mathematics, mathematical study of continuous change, in the same way that geometry is the study of shape, and algebra is the study of generalizati ...
. OpenCV has Python bindings with a rich set of features for
computer vision Computer vision is an Interdisciplinarity, interdisciplinary scientific field that deals with how computers can gain high-level understanding from digital images or videos. From the perspective of engineering, it seeks to understand and automate t ...
and
image processing An image is a visual representation of something. It can be two-dimensional, three-dimensional, or somehow otherwise feed into the visual system to convey information. An image can be an artifact, such as a photograph or other two-dimensiona ...
. Python is commonly used in
artificial intelligence Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animal cognition, animals and human intelligence, humans. Example tasks in ...
projects and machine learning projects with the help of libraries like TensorFlow, Keras, Pytorch, and scikit-learn. As a scripting language with a modular architecture, simple syntax, and rich text processing tools, Python is often used for
natural language processing Natural language processing (NLP) is an interdisciplinary subfield of linguistics, computer science, and artificial intelligence concerned with the interactions between computers and human language, in particular how to program computers to proc ...
. Python can also be used to create games, with libraries such as Pygame, which can make 2D games. Python has been successfully embedded in many software products as a scripting language, including in
finite element method The finite element method (FEM) is a popular method for numerically solving differential equations arising in engineering and mathematical models, mathematical modeling. Typical problem areas of interest include the traditional fields of struct ...
software such as Abaqus, 3D parametric modelers like FreeCAD, 3D animation packages such as 3ds Max,
Blender A blender (sometimes called a mixer or liquidiser in British English) is a kitchen appliance, kitchen and laboratory appliance used to mix, crush, purée or emulsion, emulsify food and other substances. A stationary blender consists of a blender ...
, Cinema 4D, Lightwave,
Houdini Harry Houdini (, born Erik Weisz; March 24, 1874 – October 31, 1926) was a Hungarian-American escape artist, magic man, and stunt performer A stunt performer, often called a stuntman or stuntwoman and occasionally stuntperson or stunt- ...
,
Maya Maya may refer to: Civilizations * Maya peoples, of southern Mexico and northern Central America ** Maya civilization, the historical civilization of the Maya peoples ** Maya language (disambiguation), Maya language, the languages of the Maya peop ...
, modo, MotionBuilder, Softimage, the visual effects compositor Nuke, 2D imaging programs like
GIMP GIMP ( ; GNU Image Manipulation Program) is a free and open-source raster graphics editor used for image manipulation (retouching) and image editing, free-form drawing, transcoding between different image file formats, and more specialized task ...
,
Inkscape Inkscape is a free and open-source software, free and open-source vector graphics editor used to create vector images, primarily in Scalable Vector Graphics (SVG) format. Other formats can be imported and exported. Inkscape can Rendering (com ...
, Scribus and Paint Shop Pro, and
musical notation Music notation or musical notation is any system used to visually represent wikt:aurally, aurally perceived music played with instrument (music), instruments or singing, sung by the human voice through the use of written, printed, or otherwise ...
programs like
scorewriter A scorewriter, or music notation program is software for creating, editing and printing sheet music. A scorewriter is to music notation what a word processor is to text, in that they typically provide flexible editing and automatic layout, and pr ...
and capella.
GNU Debugger The GNU Debugger (GDB) is a Software portability, portable debugger that runs on many Unix-like systems and works for many programming languages, including Ada (programming language), Ada, C (programming language), C, C++, Objective-C, Free Pasc ...
uses Python as a pretty printer to show complex structures such as C++ containers.
Esri Esri (; Environmental Systems Research Institute) is an American Multinational corporation, multinational geographic information system (GIS) software company. It is best known for its ArcGIS products. With a 43% market share, Esri is the world' ...
promotes Python as the best choice for writing scripts in
ArcGIS ArcGIS is a family of client software, client, server software, server and online geographic information system (GIS) software developed and maintained by Esri. ArcGIS was first released in 1999 and originally was released as ArcInfo, ARC/INFO, a ...
. It has also been used in several video games, and has been adopted as first of the three available programming languages in Google App Engine, the other two being Java (software platform), Java and Go. Many operating systems include Python as a standard component. It ships with most Linux distributions, AmigaOS 4 (using Python 2.7), FreeBSD (as a package), NetBSD, and OpenBSD (as a package) and can be used from the command line (terminal). Many Linux distributions use installers written in Python: Ubuntu (operating system), Ubuntu uses the Ubiquity (software), Ubiquity installer, while Red Hat Linux and Fedora Linux use the Anaconda (installer), Anaconda installer. Gentoo Linux uses Python in its package management system, Portage (software), Portage. Python is used extensively in the information security industry, including in exploit development. Most of the Sugar (software), Sugar software for the One Laptop per Child XO, developed at Sugar Labs since 2008, is written in Python. The Raspberry Pi single-board computer project has adopted Python as its main user-programming language. LibreOffice includes Python and intends to replace Java with Python. Its Python Scripting Provider is a core feature since Version 4.0 from 7 February 2013.


Languages influenced by Python

Python's design and philosophy have influenced many other programming languages: * Boo (programming language), Boo uses indentation, a similar syntax, and a similar object model. * Cobra (programming language), Cobra uses indentation and a similar syntax, and its ''Acknowledgements'' document lists Python first among languages that influenced it. * CoffeeScript, a programming language that cross-compiles to JavaScript, has Python-inspired syntax. * ECMAScript/
JavaScript JavaScript (), often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web The World Wide Web (WWW), commonly known as the Web, is an information system enabling documents and oth ...
borrowed iterators and generator (computer science), generators from Python. * GDScript, a scripting language very similar to Python, built-in to the Godot (game engine), Godot game engine. * Go is designed for the "speed of working in a dynamic language like Python" and shares the same syntax for slicing arrays. * Groovy (programming language), Groovy was motivated by the desire to bring the Python design philosophy to
Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...
. * Julia (programming language), Julia was designed to be "as usable for general programming as Python". * Nim (programming language), Nim uses indentation and similar syntax. *
Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapp ...
's creator, Yukihiro Matsumoto, has said: "I wanted a scripting language that was more powerful than Perl, and more object-oriented than Python. That's why I decided to design my own language." * Swift (programming language), Swift, a programming language developed by Apple, has some Python-inspired syntax. Python's development practices have also been emulated by other languages. For example, the practice of requiring a document describing the rationale for, and issues surrounding, a change to the language (in Python, a PEP) is also used in Tcl, Erlang (programming language), Erlang, and Swift.


See also

* Python syntax and semantics * pip (package manager) * List of programming languages * History of programming languages * Comparison of programming languages


References


Sources

* * * *


Further reading

* * * * * * * Ramalho, Luciano (May 2022).
Fluent Python
' (2nd ed.). O'Reilly Media. ISBN (identifier), ISBN Special:BookSources/978-1-4920-5632-4, 978-1-4920-5632-4.


External links

* Python (programming language), Articles with example Python (programming language) code Class-based programming languages Notebook interface Computer science in the Netherlands Concurrent programming languages Cross-platform free software Cross-platform software Dutch inventions Dynamically typed programming languages Educational programming languages High-level programming languages Information technology in the Netherlands Multi-paradigm programming languages Object-oriented programming languages Pattern matching programming languages Programming languages Programming languages created in 1991 Scripting languages Text-oriented programming languages {{Good article