Functions in Python

In this part of the tutorial, we are going to discuss about Function in python. Before going into it, Let’s have a quick recap to the Python Basics we had previously completed.

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When programming, you will encounter the calculation and logical operation you need to perform  repeatedly. One way to handle this is to write the same code over. A better solution is to write a function, function enable you to reuse the logic an infinite number of times without repeating yourself.

Time to begin,

Definition

A function is a block of code which runs in a certain oreder  is called it by name. It can be passed data to operate on  the parameters and can return value. All data that is passed to a function is explicitly passed.

Benefits of Python Function

•          Reuse of code
•          Reducing duplication of code
•          Decomposing complex problems into simpler pieces
•          Improving clarity of the code
•          Information hiding

Basic Syntax of Function

def function_name(parameters):

                """docstring"""

                statement(s)

Let see,

How to create a function in python?

A function is defined by using def keyword

Here’s one

To define a function, you write def followed by the name of the function

def my_function(name):

print(“Hi ,”+name+ “ .  Happy Morning”)

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How to call a function?

Once we have defined a function, we can call it from another function. To call a function  simply use  the function name with appropriate parameters.

>>> myfunction('Yuvi’)

Hello, Yuvi. Happy morning!

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Docstring

The first string after the function header is called the docstring and is short for documentation string. It is used to explain in brief, what a function does.

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The  Return Statement

The statement return execute a function and passing back to the  place where it was called

Syntax  : return [expression_list]

Example,

def sum( arg1, arg2 ):

 # Add both the parameters and return them."

   total = arg1 + arg2

   print "Inside the function : ", total

   return total;

# Now you can call sum function

total = sum( 10, 20 );

print "Outside the function : ", total

Output :

Outside the function :  30

Inside the function :  30

Check out :  Installation of Python

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Scope of Variable

All variables in a program that cannot be accessible at all the location so it based on where you have declared a variable. There are two basic scopes of  variables in python ,

•          Local variables
•          Global variables

Local and Global Variable

Scope of a variable is the portion of a program where the parameters and variables defined inside a function is not visible from outside. Hence, they have a local varaibles.

On the otherhand, Global variables can be accessed through the entire program body by all functions.

def my_func()

x = 10

print("Value inside function:",x)

x = 20

my_func()

print("Value outside function:",x)

Output :

Value inside function: 10

Value outside function: 20

Here is the Complete Python Course Content (PDF Download).