Python Coding challenge - Day 673| What is the output of the following Python Code?

 

Code Explanation

Step 1: Function Definition

def append_item(item, container=[]):

    container.append(item)

    return container

A function append_item is defined with two parameters:

item: the value to add.

container: defaults to [] (an empty list).

Important: In Python, default argument values are evaluated once at function definition time, not every time the function is called.

That means the same list ([]) is reused across calls if no new list is passed.

Step 2: First Call

print(append_item(1), ...)

append_item(1) is called.

Since no container argument is provided, Python uses the default list (currently []).

Inside the function:

container.append(1) → list becomes [1].

return container → returns [1].

So, the first value printed is [1].

Step 3: Second Call

print(..., append_item(2))

append_item(2) is called.

Again, no container is passed, so Python uses the same list that was used before ([1]).

Inside the function:

container.append(2) → list becomes [1, 2].

return container → returns [1, 2].

So, the second value printed is [1, 2].

Step 4: Final Output

print(append_item(1), append_item(2))

First call returned [1].

Second call returned [1, 2].

Final Output:

[1] [1, 2]

Download Book - 500 Days Python Coding Challenges with Explanation