Python Coding challenge - Day 575| What is the output of the following Python Code?

 

Code Explanation:

Function Definition

def f(x, y=[]):

    for i in range(x):

        y.append(i)

    return y

Parameters:

x: How many numbers to append (from 0 to x-1)

y: A list to which numbers will be appended. Default is a mutable list []

Function Calls

Call 1:

print(f(2))

x = 2, y not passed → uses shared default list.

Loop appends 0, 1 → y = [0, 1]

Returns: [0, 1]

Call 2:

print(f(3, []))

x = 3, y = [] → a new list is passed explicitly.

Loop appends 0, 1, 2 → y = [0, 1, 2]

Returns: [0, 1, 2]

This one is isolated from the shared default list.

Call 3:

print(f(2))

x = 2, y not passed → again uses the shared default list, which already contains [0, 1] from Call 1.

Appends 0, 1 again → y = [0, 1, 0, 1]

Returns: [0, 1, 0, 1]

Final Output:

[0, 1]

[0, 1, 2]

[0, 1, 0, 1]

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