A built-in function is a function that is already available in a programming language, application, or another tool that can be accessed by end users. For example, most spreadsheet applications support a built-in SUM function that adds up all cells in a row or column.
The term “built-in” refers to the fact that these functions are part of the core functionality of the language or tool and are not added by an external library or module. In fact, built-in functions can be accessed without having to import any modules. This makes them faster than regular functions because they do not have to go through an extra step before being called.
In Python, for example, all mathematical operations, such as addition (+), subtraction (-), multiplication (*), and division (/) are built into the language itself, so users don’t need to import anything else in order to use these operations. Built-in functions are also called built-in procedures, system functions, or intrinsic functions.
Examples of Built-In Functions in Python
A variety of different office suites, business applications, and programming languages offer built-in functions to simplify the user experience. The following is a list of built-in functions that can be utilized in Python 3:
abs() returns absolute value (positive) of a number
acos() returns arc cosine as radians
add(x, y) adds two numbers together
any(iterable) tests whether any element in an iterable evaluates to True
apply(f, args [ , keywords]) calls function f with arguments from args and optional keyword arguments
argmax([axis, out]) finds maximum value along given axis
argmin([axis, out]) finds minimum value along given axis
arange([start], stop[ , step ]) generates sequence of evenly spaced values between start and stop