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List comprehension is a syntactic construct available in some programming languages for creating a list based on existing lists. It follows the form of the mathematical set-builder notation (set comprehension) as distinct from the use of map and filter functions.
Local variables may have a lexical or dynamic scope, though lexical (static) scoping is far more common.In lexical scoping (or lexical scope; also called static scoping or static scope), if a variable name's scope is a certain block, then its scope is the program text of the block definition: within that block's text, the variable name exists, and is bound to the variable's value, but outside ...
In most programming languages, functions may take one or more arguments. Usually, each argument must be specified in full (this is the case in the C programming language [1]). Later languages (for example, in C++) allow the programmer to specify default arguments that always have a value, even if one is not specified when calling the function.
The term closure is often used as a synonym for anonymous function, though strictly, an anonymous function is a function literal without a name, while a closure is an instance of a function, a value, whose non-local variables have been bound either to values or to storage locations (depending on the language; see the lexical environment section below).
A typical example is the static variables in C and C++. A Stack-dynamic variable is known as local variable, which is bound when the declaration statement is executed, and it is deallocated when the procedure returns. The main examples are local variables in C subprograms and Java methods.
Local variables are defined inside a method, or a particular block. These variables are local to where they were defined and lower levels. For example, a loop inside a method can use that method's local variables, but not the other way around. The loop's variables (local to that loop) are destroyed as soon as the loop ends. Member variables
The initial design is encouraged to use the most restrictive visibility possible, in order of local (or method) variables, private variables (in object oriented programming), and global (or public) variables, and only be expanded when and as much as necessary. This prevents changes to visibility from invalidating existing code. [45]
In some languages, for example C++, Java, and Raku this or self is a keyword, and the variable automatically exists in instance methods. In others, for example, Python, Rust, and Perl 5, the first parameter of an instance method is such a reference. It needs to be specified explicitly.