Python Function

 

Function

A function in Python is an aggregation of related statements designed to perform a computational, logical, or evaluative task. The idea is to put some commonly or repeatedly done task together and make a function so that instead of writing the same code again and again for different inputs, we can call the function. 

Functions can be both built-in or user-defined. It helps the program to be concise, non-repetitive, and organized.

Syntax: 

def function_name(parameters):

    """docstring"""

    statement(s)

Example:

Program:

# A simple Python function to check # whether x is even or odd def evenOdd(x):   if (x % 2 == 0):     print("even")   else:     print("odd") # Driver code evenOdd(2) evenOdd(3) # Scripts Ends

Output:

even odd

 

Rules for naming python function (identifier)

1. It can begin with either of the following: A-Z, a-z, and underscore(_).

2. The rest of it can contain either of the following: A-Z, a-z, digits(0-9), and underscore(_).

3. A reserved keyword may not be chosen as an identifier.

It is good practice to name a Python function according to what it does.

Python Function Parameters

Sometimes, you may want a function to operate on some variables, and produce a result. Such a function may take any number of parameters. Let’s take a function to add two numbers.

Example:

Program:

def sum(a,b):     c=a+b     print(c) #Function complete #call sum function with parameters sum(5,6) # Scripts Ends

Output:

11

Python return statement

A Python function may optionally return a value. This value can be a result that it produced on its execution. Or it can be something you specify- an expression or a value.

Example:

Program:

def sum(a,b):     return a+b print(sum(2,3)) # Scripts Ends

Output:

5