Python Coding challenge - Day 1193| What is the output of the following Python Code?

 

Code Explanation:

🔹 1. Defining the Outer Function

def outer():

✅ Explanation:

A function named outer() is created.

This function contains another function (inner()), making it a nested function.

Current structure:

outer()

   │

   └── inner()

🔹 2. Creating a Local Variable

x = 10

✅ Explanation:

A local variable x is created inside outer().

Current memory:

outer()

x = 10

This variable belongs only to the outer() function.

🔹 3. Defining the Inner Function

def inner():

✅ Explanation:

A new function named inner() is created inside outer().

Structure becomes:

outer()

x = 10

    │

    inner()

At this point, inner() is only defined, not executed.

🔹 4. Using nonlocal

nonlocal x

✅ Explanation:

The nonlocal keyword tells Python:

"Don't create a new variable named x. Use the x from the nearest enclosing function (outer())."

Without nonlocal:

x += 5

would try to create a new local variable and raise an error.

Visual:

inner()

        │

nonlocal x

        │

Uses x from outer()

🔹 5. Updating the Variable

x += 5

✅ Explanation:

Current value of x:

x = 10

Calculation:

10 + 5

New value:

x = 15

Memory after update:

outer()

x = 15

Notice:

No new variable is created.

The original x inside outer() is modified.

🔹 6. Calling inner()

inner()

✅ Explanation:

Python executes the inner() function.

Execution steps:

inner()

↓

nonlocal x

↓

x = x + 5

↓

x becomes 15

Current state:

outer()

x = 15

🔹 7. Printing the Value

print(x)

✅ Explanation:

Python prints the value of x inside outer().

Current value:

x = 15

Output:

15

🔹 8. Calling outer()

outer()

✅ Explanation:

This starts the execution of the outer() function.

Execution flow:

outer()

↓

x = 10

↓

inner()

↓

x = 15

↓

print(x)

↓

15

🎯 Final Output

15

Book: 400 Days Python Coding Challenges with Explanation