Python – Call function from another function

Prerequisite: Functions in Python

In Python, any written function can be called by another function. Note that this could be the most elegant way of breaking a problem into chunks of small problems. In this article, we will learn how can we call a defined function from another function with help of multiple examples.

Calling and Called Function ?
The Function which calls another Function is called Calling Function and function which is called by another Function is call Called Function.

How Function execution works ?
A stack data structure is used during the execution of the function calls. Whenever a function is invoked then the calling function is pushed into the stack and called function is executed. When the called function completes its execution and returns then the calling function is popped from the stack and executed. Calling Function execution will be completed only when called Function is execution completes.

In the below figure. The function call is made from the Main function to Function1, Now the state of the Main function is stored in Stack and execution of the Main function is continued when the Function 1 returns. The Fucntion1 Calls Function2 now the State of the Function1 is stored stack and execution of Function 1 will be continued when Function 2 returns.



Consider the below Example of the function call. The Function SumOfSquares function calls the Function Square which returns the square of the number.

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python code to demonstrate calling the 
# function from another function
  
def Square(X):
    # computes the Square of the given number 
    # and return to the caller function
    return (X * X)
  
def SumofSquares(Array, n):
  
    # Initialize variable Sum to 0. It stores the 
    # Total sum of squares of the array of elements
    Sum = 0
    for i in range(n):
  
        # Square of Array[i] element is stored in SquaredValue
        SquaredValue = Square(Array[i])
  
        # Cummulative sum is stored in Sum variable
        Sum += SquaredValue
    return Sum
  
# Driver Function
Array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
n = len(Array)
  
# Return value from the function 
# Sum of Squares is stored in Total
Total = SumofSquares(Array, n)
print("Sum of the Square of List of Numbers:", Total)

chevron_right


Output :

Sum of the Square of List of Numbers: 385 

 
Calling Function From another Function within Same class –

In the below example, the class method Function1 calls method Function2 from the class.

filter_none

edit
close

play_arrow

link
brightness_4
code

'''
Call a function from within another function
in the same class in Python 
'''
  
class Main:
  
    # constructor of Main class
    def __init__(self):
        # Initialization of the Strings
        self.String1 ="Hello"
        self.String2 ="World"
  
    def Function1(self):
        # calling Function2 Method
        self.Function2()
        print("Function1 : ", self.String2)
        return 
  
    def Function2(self):
        print("Function2 : ", self.String1)
        return
  
# Instance of Class Main
Object = Main()
  
# Calling Function1
Object.Function1()

chevron_right


Output :

Function2 :  Hello
Function1 :  World

 

Calling parent class Function from Child class Function –

Consider the below example the child class method invokes the parent class method. The child class inherits the attributes from the parent class.

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python code to demonstrate calling parent class 
# method from the child class method
  
class Parent:
  
    # constructor of Parent class
    def __init__(self):
        # Initialization of the Strings
        self.String1 ="Hello"
        self.String2 ="World"
  
    def Function2(self):
        print("Function2 : ", self.String1)
        return
  
# Child class is inheriting from Parent class
class Child(Parent):
  
    def Function1(self):
        # calling Function2 Method in parent class 
        self.Function2()
        print("Function1 : ", self.String2)
        return   
  
### Instance of Parent class
Object1 = Parent()
  
### Instance of Child class
Object2 = Child()
  
# Calling Function1 using Child class instance
Object2.Function1()

chevron_right


Output :

Function2 :  Hello
Function1 :  World



My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.


Article Tags :

2


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.