Python Coding challenge - Day 480| What is the output of the following Python Code?

 

Code Explanation:

Function Definition

def f(x, acc=[]):

    acc.append(x)

    if x > 0:

        return f(x - 1, acc)

    return sum(acc)

Parameters:

x: An integer passed to the function.

acc: A mutable default argument (list), which accumulates values during recursion.

Initial Call: f(3)

When f(3) is called:

x = 3, and the default list acc = [] is used since no other list is provided.

3 is appended to acc, so acc = [3].

The condition x > 0 is true, so the function calls f(2, [3]).

Second Call: f(2, [3])

x = 2, and the list acc = [3] is passed.

2 is appended to acc, so acc = [3, 2].

The condition x > 0 is still true, so the function calls f(1, [3, 2]).

Third Call: f(1, [3, 2])

x = 1, and the list acc = [3, 2] is passed.

1 is appended to acc, so acc = [3, 2, 1].

The condition x > 0 is still true, so the function calls f(0, [3, 2, 1]).

Fourth Call: f(0, [3, 2, 1])

x = 0, and the list acc = [3, 2, 1] is passed.

0 is appended to acc, so acc = [3, 2, 1, 0].

The condition x > 0 is false, so it returns the sum of the list acc, which is sum([3, 2, 1, 0]) = 6.

Final Return Value

The function returns 6, and the final output is printed as:

6