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74-647: Strings and other concrete objects are typically expressed as immutable objects to improve readability and runtime efficiency in OO programming. Immutable objects are also useful because they are inherently thread-safe . Other benefits are that they are simpler to understand and reason about and offer higher security than mutable objects. In imperative programming , values held in program variables whose content never changes are known as constants to differentiate them from variables that could be altered during execution. Examples include conversion factors from meters to feet, or

148-425: A member variable be changed from within a const method. In D , there exist two type qualifiers , const and immutable , for variables that cannot be changed. Unlike C++'s const , Java's final , and C#'s readonly , they are transitive and recursively apply to anything reachable through references of such a variable. The difference between const and immutable is what they apply to: const

222-505: A . However, maintaining the validity of this equation means that while the result of a%b is, as expected, in the half-open interval [0, b ), where b is a positive integer, it has to lie in the interval ( b , 0] when b is negative. Python provides a round function for rounding 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)

296-419: A certain type. Python does not support tail call optimization or first-class continuations , and, according to Van Rossum, it never will. However, better support for coroutine -like functionality is provided by extending Python's generators . Before 2.5, generators were lazy iterators ; data was passed unidirectionally out of the generator. From Python 2.5 on, it is possible to pass data back into

370-648: A combination of reference counting and a cycle-detecting garbage collector for memory management . 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 tradition. It has filter , map and reduce functions; list comprehensions , dictionaries , sets, and generator expressions. The standard library has two modules ( itertools and functools ) that implement functional tools borrowed from Haskell and Standard ML . Its core philosophy

444-420: 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. Python's statements include: The assignment statement ( = ) binds

518-483: A function of type inout(S) function(inout(T)) returns S for mutable T arguments, const(S) for const(T) values, and immutable(S) for immutable(T) values. Casting immutable values to mutable inflicts undefined behavior upon change, even if the original value comes from a mutable origin. Casting mutable values to immutable can be legal when there remain no mutable references afterward. "An expression may be converted from mutable (...) to immutable if

592-510: A generator function; and from version 3.3, it can be passed through multiple stack levels. Python's expressions include: In Python, a distinction between expressions and statements is rigidly enforced, in contrast to languages such as Common Lisp , Scheme , or Ruby . This leads to duplicating some functionality. For example: 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

666-428: 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. While Python 2.7 and older versions are officially unsupported, a different unofficial Python implementation, PyPy , continues to support Python 2, i.e. "2.7.18+" (plus 3.10), with the plus meaning (at least some) " backported security updates". Python 3.0

740-445: A matrix‑multiplication operator @ . These operators work like in traditional math; with the same precedence rules , the operators infix ( + 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: In Python terms, / is true division (or simply division ), and //

814-401: A mutable references library or a foreign function interface ), so all objects are immutable. In Ada , any object is declared either variable (i.e. mutable; typically the implicit default), or constant (i.e. immutable) via the constant keyword. Subprogram parameters are immutable in the in mode, and mutable in the in out and out modes. In C# you can enforce immutability of

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888-399: A mutex is used to synchronize all access to the shared counter variable. But if the function is used in a reentrant interrupt handler and a second interrupt arises while the mutex is locked, the second routine will hang forever. As interrupt servicing can disable other interrupts, the whole system could suffer. The same function can be implemented to be both thread-safe and reentrant using

962-402: A name as a reference 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 ; however, it always refers to some object with a type. This is called dynamic typing —in contrast to statically-typed languages, where each variable may contain only a value of

1036-461: A new and improved interactive interpreter ( REPL ), featuring multi-line editing and color support; an incremental garbage collector (producing shorter pauses for collection in programs with a lot of objects, and addition to the improved speed in 3.11 and 3.12), and an experimental just-in-time (JIT) compiler (such features, can/needs to be enabled specifically for the increase in speed), and an experimental free-threaded build mode, which disables

1110-624: A new value. The use of immutable state has become a rising trend in JavaScript since the introduction of React , which favours Flux-like state management patterns such as Redux . In Perl , one can create an immutable class with the Moo library by simply declaring all the attributes read only: Creating an immutable class used to require two steps: first, creating accessors (either automatically or manually) that prevent modification of object attributes, and secondly, preventing direct modification of

1184-409: A pointer and a length filed, and safe, as the underlying data cannot be changed. Objects of type const(char)[] can refer to strings, but also to mutable buffers. Making a shallow copy of a const or immutable value removes the outer layer of immutability: Copying an immutable string ( immutable(char[]) ) returns a string ( immutable(char)[] ). The immutable pointer and length are being copied and

1258-446: A program using such a library is thread-safe depends on whether it uses the library in a manner consistent with those guarantees. Below we discuss two classes of approaches for avoiding race conditions to achieve thread-safety. The first class of approaches focuses on avoiding shared state and includes: The second class of approaches are synchronization-related, and are used in situations where shared state cannot be avoided: In

1332-531: A shared address space and each of those threads has access to every other thread's memory , thread-safe functions need to ensure that all those threads behave properly and fulfill their design specifications without unintended interaction. There are various strategies for making thread-safe data structures. Different vendors use slightly different terminology for thread-safety, but the most commonly use thread-safety terminology are: Thread safety guarantees usually also include design steps to prevent or limit

1406-411: A standard format for distributing Python Binaries. Python 3.15 will "Make UTF-8 mode default", the mode exists in all current Python versions, but currently needs to be opted into. UTF-8 is already used, by default, on Windows (and elsewhere), for most things, but e.g. to open files it's not and enabling also makes code fully cross-platform, i.e. use UTF-8 for everything on all platforms. Python

1480-653: A string literal, with no certainty as to which one a programmer should use. Alex Martelli , a Fellow 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 usually strive to avoid premature optimization and reject patches to non-critical parts of the CPython reference implementation that would offer marginal increases in speed at

1554-536: Is StringBuilder (mutable version of .Net String ). Python 3 has a mutable string (bytes) variant, named bytearray . Additionally, all of the primitive wrapper classes in Java are immutable. Similar patterns are the Immutable Interface and Immutable Wrapper . In pure functional programming languages it is not possible to create mutable objects without extending the language (e.g. via

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1628-585: 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

1702-403: 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 ( a + b ) // b == a // b + 1 is always true. It also means that the equation b * ( a // b ) + a % b == a is valid for both positive and negative values of

1776-522: Is a multi-paradigm programming language . Object-oriented programming and structured programming are fully supported, and many of their features support functional programming and aspect-oriented programming (including metaprogramming and metaobjects ). Many other paradigms are supported via extensions, including design by contract and logic programming . Python is known as a glue language , able to work very well with many other languages with ease of access. Python uses dynamic typing and

1850-456: Is a property of the variable: there might legally exist mutable references to referred value, i.e. the value can actually change. In contrast, immutable is a property of the referred value: the value and anything transitively reachable from it cannot change (without breaking the type system, leading to undefined behavior ). Any reference of that value must be marked const or immutable . Basically for any unqualified type T , const(T)

1924-416: Is an alternative technique for handling changes to mutable objects. A technique that blends the advantages of mutable and immutable objects, and is supported directly in almost all modern hardware, is copy-on-write (COW). Using this technique, when a user asks the system to copy an object, it instead merely creates a new reference that still points to the same object. As soon as a user attempts to modify

1998-497: Is compiled, and possibly semantics are slightly changed. 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 —and in occasionally playful approaches to tutorials and reference materials, such as the use of the terms "spam" and "eggs" (a reference to a Monty Python sketch ) in examples, instead of the often-used "foo" and "bar" . A common neologism in

2072-407: Is generally only useful for immutable objects. Immutable objects can be useful in multi-threaded applications. Multiple threads can act on data represented by immutable objects without concern of the data being changed by other threads. Immutable objects are therefore considered more thread-safe than mutable objects. Immutability does not imply that the object as stored in the computer's memory

2146-532: 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 . Python uses whitespace indentation, rather than curly brackets or keywords, to delimit blocks . An increase in indentation comes after certain statements;

2220-458: Is midway through checking it. This difficult-to-diagnose logic error , which may compile and run properly most of the time, is called a race condition . One common way to avoid this is to use another shared variable as a "lock" or "mutex" (from mut ual ex clusion). In the following piece of C code, the function is thread-safe, but not reentrant: In the above, increment_counter can be called by different threads without any problem since

2294-426: Is much more difficult to use for mutable objects, because if any user of a mutable object reference changes it, all other users of that reference see the change. If this is not the intended effect, it can be difficult to notify the other users to have them respond correctly. In these situations, defensive copying of the entire object rather than the reference is usually an easy but costly solution. The observer pattern

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2368-401: Is not necessary — and in fact impossible — to provide a specialized constructor for const instances.) Note that, when there is a data member that is a pointer or reference to another object, then it is possible to mutate the object pointed to or referenced only within a non-const method. C++ also provides abstract (as opposed to bitwise) immutability via the mutable keyword, which lets

2442-411: 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 . New instances of classes are constructed by calling

2516-505: Is often described as a "batteries included" language due to its comprehensive standard library . 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. Python 3.0, released in 2008, was a major revision not completely backward-compatible with earlier versions. Python 2.7.18, released in 2020,

2590-508: Is popular in virtual memory systems because it allows them to save memory space while still correctly handling anything an application program might do. The practice of always using references in place of copies of equal objects is known as interning . If interning is used, two objects are considered equal if and only if their references, typically represented as pointers or integers, are equal. Some languages do this automatically: for example, Python automatically interns short strings . If

2664-402: Is roughly equivalent to the above, plus some tuple-like features: Thread safety In multi-threaded computer programming , a function is thread-safe when it can be invoked or accessed concurrently by multiple threads without causing unexpected behavior, race conditions , or data corruption. As in the multi-threaded context where a program executes several threads simultaneously in

2738-434: Is self-titled "BDFL-emeritus"). 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 such as list comprehensions , cycle-detecting garbage collection, reference counting , and Unicode support. Python 2.7's end-of-life was initially set for 2015, then postponed to 2020 out of concern that

2812-610: Is slow, inconsistent and buggy [and it has] has many corner cases and oddities. Code that works around those may need to be changed. Code that uses locals() for simple templating, or print debugging, will continue to work correctly." Some (more) standard library modules and many deprecated classes, functions and methods, will be removed in Python 3.15 or 3.16. Python 3.14 is now in alpha 2; regarding possible change to annotations: "In Python 3.14, from __future__ import annotations will continue to work as it did before, converting annotations into strings." PEP 711 proposes PyBI:

2886-549: Is summarized in the Zen of Python (PEP 20), which includes aphorisms such as: However, Python features regularly violate these principles and have received criticism for adding unnecessary language bloat. Responses to these criticisms are that the Zen of Python is a guideline rather than a rule. The addition of some new features had been so controversial that Guido van Rossum resigned as Benevolent Dictator for Life following vitriol over

2960-460: Is that an assignment statement such as a = 1 cannot form part of the conditional expression of a conditional statement. Methods on objects are functions attached to the object's class; the syntax instance . method ( argument ) is, for normal methods and functions, syntactic sugar for Class . method ( instance , argument ) . Python methods have an explicit self parameter to access instance data , in contrast to

3034-504: Is the disjoint union of T (mutable) and immutable(T) . For a mutable C object, its mField can be written to. For a const(C) object, mField cannot be modified, it inherits const ; iField is still immutable as it is the stronger guarantee. For an immutable(C) , all fields are immutable. In a function like this: Inside the braces, c might refer to the same object as m , so mutations to m could indirectly change c as well. Also, c might refer to

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3108-685: Is the oldest supported version of Python (albeit in the 'security support' phase), due to Python 3.8 reaching end-of-life . Starting with 3.13, it and later versions have 2 years of full support (up from one and a half), followed by 3 years of security support (for same total support as before). Security updates were expedited in 2021 (and again twice in 2022, and more fixed in 2023 and in September 2024 for Python 3.12.6 down to 3.8.20), since all Python versions were insecure (including 2.7 ) because of security issues leading to possible remote code execution and web-cache poisoning . Python 3.10 added

3182-556: Is unwriteable. Rather, immutability is a compile-time construct that indicates what a programmer can do through the normal interface of the object, not necessarily what they can absolutely do (for instance, by circumventing the type system or violating const correctness in C or C++ ). In Python , Java and the .NET Framework , strings are immutable objects. Both Java and the .NET Framework have mutable versions of string. In Java these are StringBuffer and StringBuilder (mutable versions of Java String ) and in .NET this

3256-548: 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 numbers . 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. "Hello, World!" program : Program to calculate

3330-541: The final keyword. final only prevents reassignment. Primitive wrappers ( Integer , Long , Short , Double , Float , Character , Byte , Boolean ) are also all immutable. Immutable classes can be implemented by following a few simple guidelines. In JavaScript , all primitive types (Undefined, Null, Boolean, Number, BigInt, String, Symbol) are immutable, but custom objects are generally mutable. To simulate immutability in an object, one may define properties as read-only (writable: false). However,

3404-570: The | union type operator and the match and case keywords (for structural pattern matching statements). 3.11 expanded exception handling functionality. Python 3.12 added the new keyword type . Notable changes in 3.11 from 3.10 include increased program execution speed and improved error reporting. Python 3.11 claims to be between 10 and 60% faster than Python 3.10, and Python 3.12 adds another 5% on top of that. It also has improved error messages (again improved in 3.14), and many other changes. Python 3.13 introduces more syntax for types,

3478-582: The Amoeba 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 " (BDFL), a title the Python community bestowed upon him to reflect his long-term commitment as the project's chief decision-maker (he has since come out of retirement and

3552-491: The global interpreter lock (GIL), allowing threads to run more concurrently, that latter feature enabled with python3.13t or python3.13t.exe . Python 3.13 introduces some change in behavior, i.e. new "well-defined semantics", fixing bugs (plus many removals of deprecated classes, functions and methods, and removed some of the C ;API and outdated modules): "The [old] implementation of locals() and frame.f_locals

3626-403: 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

3700-497: The addition of the assignment expression operator in Python 3.8. Nevertheless, 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

3774-421: The algorithm that implements interning is guaranteed to do so in every case that it is possible, then comparing objects for equality is reduced to comparing their pointers – a substantial gain in speed in most applications. (Even if the algorithm is not guaranteed to be comprehensive, there still exists the possibility of a fast path case improvement when the objects are equal and use the same reference.) Interning

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3848-403: The approach above still lets new properties be added. Alternatively, one may use Object.freeze to make existing objects immutable. With the implementation of ECMA262 , JavaScript has the ability to create immutable references that cannot be reassigned. However, using a const declaration doesn't mean that value of the read-only reference is immutable, just that the name cannot be assigned to

3922-475: The class (for example, SpamClass () or EggsClass () ), and the classes are instances of the metaclass 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 of the new style. Python supports optional type annotations . These annotations are not enforced by

3996-478: The copies are mutable. The referred data has not been copied and keeps its qualifier, in the example immutable . It can be stripped by making a depper copy, e.g. using the dup function. A classic example of an immutable object is an instance of the Java String class The method toLowerCase() does not change the data "ABC" that s contains. Instead, a new String object is instantiated and given

4070-399: The cost of clarity. Execution speed can be improved by moving speed-critical functions to extension modules written in languages such as C, or by using a just-in-time compiler like PyPy . It is also possible to cross-compile to other languages , but it either doesn't provide the full speed-up that might be expected, since Python is a very dynamic language , or a restricted subset of Python

4144-485: The data "abc" during its construction. A reference to this String object is returned by the toLowerCase() method. To make the String s contain the data "abc", a different approach is needed: Now the String s references a new String object that contains "abc". There is nothing in the syntax of the declaration of the class String that enforces it as immutable; rather, none of the String class's methods ever affect

4218-473: The data that a String object contains, thus making it immutable. The keyword final ( detailed article ) is used in implementing immutable primitive types and object references, but it cannot, by itself, make the objects themselves immutable. See below examples: Primitive type variables ( int , long , short , etc.) can be reassigned after being defined. This can be prevented by using final . Reference types cannot be made immutable just by using

4292-428: The expression is unique and all expressions it transitively refers to are either unique or immutable." If the compiler cannot prove uniqueness, the casting can be done explicitly and it is up to the programmer to ensure that no mutable references exist. The type string is an alias for immutable(char)[] , i.e. a typed slice of memory of immutable characters. Making substrings is cheap, as it just copies and modifies

4366-481: The fields of a class with the readonly statement. By enforcing all the fields as immutable, you obtain an immutable type. C# have records which are immutable. In C++, a const-correct implementation of Cart would allow the user to create instances of the class and then use them as either const (immutable) or mutable, as desired, by providing two different versions of the items() method. (Notice that in C++ it

4440-407: The following piece of Java code, the Java keyword synchronized makes the method thread-safe: In the C programming language , each thread has its own stack. However, a static variable is not kept on the stack; all threads share simultaneous access to it. If multiple threads overlap while running the same function, it is possible that a static variable might be changed by one thread while another

4514-609: The implicit self (or this ) in some other object-oriented programming languages (e.g., C++ , Java , Objective-C , Ruby ). 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 and type conversion. Python uses duck typing and has typed objects but untyped variable names. Type constraints are not checked at compile time ; rather, operations on an object may fail, signifying that it

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4588-616: The instance data of instances of that class (this was usually stored in a hash reference, and could be locked with Hash::Util's lock_hash function): Or, with a manually written accessor: In Python , some built-in types (numbers, Booleans, strings, tuples, frozensets) are immutable, but custom classes are generally mutable. To simulate immutability in a class, one could override attribute setting and deletion to raise exceptions: The standard library helpers collections.namedtuple and typing.NamedTuple , available from Python 3.6 onward, create simple immutable classes. The following example

4662-507: The language, but may be used by external tools such as mypy to catch errors. Mypy also supports a Python compiler called mypyc, which leverages type annotations for optimization. 1.33333 Python has the usual symbols for arithmetic operators ( + , - , * , / ), the floor division operator // and the modulo operation % (where the remainder can be negative, e.g. 4 % -3 == -2 ). It also has ** for exponentiation , e.g. 5**3 == 125 and 9**0.5 == 3.0 , and

4736-500: The lock-free atomics in C++11 : Python (programming language) Python is a high-level , general-purpose programming language . Its design philosophy emphasizes code readability with the use of significant indentation . Python is dynamically typed and garbage-collected . It supports multiple programming paradigms , including structured (particularly procedural ), object-oriented and functional programming . It

4810-970: The object is immutable. If the whole object cannot be extended by another class, the object is called strongly immutable . This might, for example, help to explicitly enforce certain invariants about certain data in the object staying the same through the lifetime of the object. In some languages, this is done with a keyword (e.g. const in C++ , final in Java ) that designates the field as immutable. Some languages reverse it: in OCaml , fields of an object or record are by default immutable, and must be explicitly marked with mutable to be so. In most object-oriented languages , objects can be referred to using references . Some examples of such languages are Java , C++ , C# , VB.NET , and many scripting languages , such as Perl , Python , and Ruby . In this case, it matters whether

4884-468: The object through a particular reference, the system makes a real copy, applies the modification to that, and sets the reference to refer to the new copy. The other users are unaffected, because they still refer to the original object. Therefore, under COW, all users appear to have a mutable version of their objects, although in the case that users do not modify their objects, the space-saving and speed advantages of immutable objects are preserved. Copy-on-write

4958-458: The opposite approach. Python claims to strive for a simpler, less-cluttered syntax and grammar while giving developers a choice in their coding methodology. In contrast to Perl '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. In practice, however, Python provides many ways to achieve the same task. There are, for example, at least three ways to format

5032-467: The risk of different forms of deadlocks , as well as optimizations to maximize concurrent performance. However, deadlock-free guarantees cannot always be given, since deadlocks can be caused by callbacks and violation of architectural layering independent of the library itself. Software libraries can provide certain thread-safety guarantees. For example, concurrent reads might be guaranteed to be thread-safe, but concurrent writes might not be. Whether

5106-411: The same object as i , but since the value then is immutable, there are no changes. However, m and i cannot legally refer to the same object. In the language of guarantees, mutable has no guarantees (the function might change the object), const is an outward-only guarantee that the function will not change anything, and immutable is a bidirectional guarantee (the function will not change

5180-399: The state of an object can vary when objects are shared via references. If an object is known to be immutable, it is preferred to create a reference of it instead of copying the entire object. This is done to conserve memory by preventing data duplication and avoid calls to constructors and destructors; it also results in a potential boost in execution speed. The reference copying technique

5254-489: The value and the caller must not change it). Values that are const or immutable must be initialized by direct assignment at the point of declaration or by a constructor . Because const parameters forget if the value was mutable or not, a similar construct, inout , acts, in a sense, as a variable for mutability information. A function of type const(S) function(const(T)) returns const(S) typed values for mutable, const and immutable arguments. In contrast,

5328-456: The value of pi to several decimal places. Read-only fields may be calculated when the program runs (unlike constants, which are known beforehand), but never change after they are initialized. Sometimes, one talks of certain fields of an object being immutable. This means that there is no way to change those parts of the object state, even though other parts of the object may be changeable ( weakly immutable ). If all fields are immutable, then

5402-506: Was released on 3 December 2008, with some new semantics and changed syntax. At least every Python release since (now unsupported) 3.5 has added some syntax to the language, and a few later releases have dropped outdated modules, or changed semantics, at least in a minor way. Since 7 October 2024 , Python 3.13 is the latest stable release, and it and, for few more months, 3.12 are the only releases with active support including for bugfixes (as opposed to just for security) and Python 3.9,

5476-512: Was the last release of Python 2. Python consistently ranks as one of the most popular programming languages, and has gained widespread use in the machine learning community. Python was conceived in the late 1980s by Guido van Rossum at Centrum Wiskunde & Informatica (CWI) in the Netherlands as a successor to the ABC programming language, which was inspired by SETL , capable of exception handling and interfacing with

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