Function

A function produces a return value from a list of argument values.

Related concepts:  OperatorArgumentReturnMethod

Closest Wikipedia entry:  Subroutine — In computer programming, a function or subroutine is a sequence of program instructions that performs a specific task, packaged as a unit. This unit can then be used in programs wherever that particular task should be performed. Functions may be defined within programs, or separately in libraries that can be used by many programs.

Misconceptions about Function

15 documented Misconceptions

ArrowFunctionNoImpliedReturn — JavaScript

Even when an arrow function consists just of an expression, the return keyword must be explicitly written

ArrowFunctionRequiresFunctionKeyword — JavaScript

Arrow functions also require the keyword 'function'

CallbackParametersInCaller — JavaScript

Parameters of a callback function may be written as parameters of the caller function

DeferredReturn — Python

A return statement in the middle of a function doesn't return immediately

FunctionAsValueWithParentheses — JavaScript

To use a function as a value, one needs to have parentheses after its name

FunctionOverloading — JavaScript

It is possible to create multiple functions with the same name but with different signatures

FunctionsCannotBeImmediatelyInvoked — JavaScript

Functions cannot be called in the expression in which they are defined

FunctionsMustBeNamed — JavaScript

Every function definition requires an associated name

MultipleValuesReturn — Python

Functions can return multiple values

NoFunctionCallsChaining — JavaScript

It is not allowed to chain function calls

NumberOfParametersMatchArguments — JavaScript

Functions must be called with the same number of arguments as defined in their signature

OutsideInFunctionNesting — Python

Nested function calls are invoked outside in

OutsideInMethodNesting — Java

Nested method calls are invoked outside in

ParenthesesOnlyIfArgument — Python

() are optional for function calls without arguments

ReturnCall — Python

Return statements need () around the return value