Functions allow you to reuse code by defining blocks of code that can be called. Functions can take parameters and return values. To define a function, use the def keyword followed by the function name and parameters in parentheses. The code block is indented and starts with a colon. To call a function, use the function name followed by parentheses. Arguments can be passed into functions when calling them to provide input.

1. Prof. Neeraj Bhargava
Vishal Dutt
Department of Computer Science, School of
Engineering & System Sciences
MDS University, Ajmer

2. Function
• A function is a block of code which
only runs when it is called.
• You can pass data, known as
parameters, into a function.
• A function can return data as a
result.
• It provides a high degree of code
reusing.

3. Function Definition
 Function blocks begin with the keyword def followed
by the function name and parentheses ( ( ) ).
 Any input parameters or arguments should be placed
within these parentheses.
 The code block within every function starts with a
colon (:) and is indented.
 The statement return [expression] exits a function,
optionally passing back an expression to the caller.
 A return statement with no arguments is the same as
return None

4. Syntax:
def functionname( parameters ):
function_suite
return [expression]
Example:
def my_function():
print("Hello from a function")

5. Calling a Function
 To call a function, use the function name followed by
parenthesis.
Example
def my_function():
print("Hello from a function")
my_function()
Output
Hello from a function

6. Arguments
 Information can be passed into functions as
arguments.
 Arguments are specified after the function
name, inside the parentheses.
 You can add as many arguments as you
want, just separate them with a comma.

7. Example
def my_function(fname):
print(Hello + " fname")
my_function(“Aditya")
my_function(“Rahul")
my_function(“Khushi")
Output
Hello Aditya
Hello Rahul
Hello Khushi

8. Questions
 What do you mean by Function in Python?
 How will you define and call a function in Python?