Python Exercise: Access a function inside a function

Last update on March 29 2025 13:00:55 (UTC/GMT +8 hours)

19. Access a Function Inside a Function

Write a Python program to access a function inside a function.

Sample Solution:

Python Code:

# Define a function named 'test' that takes a parameter 'a'
def test(a):
    # Define a nested function 'add' that takes a parameter 'b'
    def add(b):
        # Declare 'a' from the outer scope as nonlocal to modify its value
        nonlocal a
        
        # Increment the value of 'a' by 1
        a += 1
        
        # Return the sum of 'a' (modified by the nonlocal statement) and 'b'
        return a + b
    
    # Return the inner function 'add' and its scope is retained due to closure
    return add

# Call the 'test' function with an argument '4' and assign the returned function to 'func'
func = test(4)

# Call the function 'func' with argument '4' and print the result
print(func(4)) 

Sample Output:

9 

Explanation:

In the exercise above the code defines nested functions and the usage of the 'nonlocal' keyword. The function "test(a)" defines a nested function "add(b)" that takes an argument 'b'. Within "add(b)", the 'nonlocal' keyword is used to modify the variable 'a' from the outer scope. The outer function "test(a)" returns the inner function "add(b)", and this returned function is assigned to the variable 'func'. Finally, it calls the function 'func' with an argument '4' and prints the result. This involves modifying the nonlocal variable 'a' and performing addition with the argument passed to 'func'.

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program that defines an outer function containing an inner function, then returns the inner function and calls it.
• Write a Python program to implement a closure where the inner function uses a variable from the outer function's scope and returns its value.
• Write a Python program to demonstrate function nesting by creating an inner function that is conditionally executed based on an argument.
• Write a Python program to use an inner function as a callback within an outer function and print the callback’s output.

Python Code Editor:

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