Functions in Python

In this lesson, you will be learning about functions in python, its use cases with some examples.

Topics covered:

• What are functions in python and why do you need them in python?
• How to create a function in Python and how to call the function?
• What are function definition and function body?
• Passing parameters or arguments to functions
• Returning values from a function

What are Functions in Python and why do you need them in Python?

Functions in python are a block or set of code or related statements that are used to perform a specific task or to reuse a specific code multiple times. Functions are both user-defined and built-in. You can pass arguments or parameters into a function. It helps to keep the program code organised and easily manageable.

Syntax:

def function_name(parameters):
    statement(s)
    return expression

How to create a function in Python?

To create a function in python, you need to use the def keyword followed by the function name. The function names are user-defined, so you can give any name (other than reserved words and keywords) to the function. If you’re using multiple words as a function name, then the words should be separated using an underscore (_).

Example:

def  simple_function():

How to call the function?

The function needs to be called to return the result. Call the function by using the function name followed by parenthesis along with the arguments.

Example:

def simple_function():
“statements”
simple_function():  #calling the function

Passing parameters or arguments to functions

Arguments or parameters are values that are passed to a function. A function can have multiple arguments in it separated by a comma (,). You need to specify the arguments in the function by mentioning them inside the parenthesis. If you do not know the solid count of arguments, you can add a ‘*’ before the arguments.

Example:

def  simple_function( x, y):
               if x>y:
            print(‘X is greater the Y)
            else:
            print(“ Y is greater than X)

Returning values from the function

To return values from a function, you need to use the return keyword. The return statement can consist of a variable, an expression, or a constant. If none of the above is present with the return statement a None object is returned.

Syntax:

return [expression_list]

 Example:

def  simple_function(a):
 return 57+a
print(simple_function(67))
print(simple_function(75))
print (simple_function(76))

Now, let us write some programs to understand more about function in python

Sample program using functions in pythonInput:

Input:

[gamipress_button type=”submit”  label=”Run Code Snippet” onclick=”window.open(‘https://coderseditor.com/?id=1352′,’_blank’)”]

def  simple_function(first, last):
    print(first +" "+last)
simple_function("Developer_Publish", "Academy")

Output:

Developer_Publish Academy

Sample program using functions in python

Input

def simple_function(x, y):
    if x>y:
        print("X is greater the Y")
    else:
        print("Y is greater than X")
    return(x,y) 
simple_function(7,5)

X is greater the Y