Python Coding challenge - Day 572| What is the output of the following Python Code?

 

Code Explanation:

1. Function Definition

def add_to(val, lst=None):

def: This keyword starts the definition of a function named add_to.

val: This is the value you want to add to a list.

lst=None: This is an optional parameter. If no list is passed, it defaults to None.

2. Handling Default Argument

    if lst is None:

        lst = []

Checks if lst is None (which it is if not explicitly passed).

If lst is None, a new empty list is created: lst = [].

This is a common Python idiom to avoid using a mutable default argument (like []), which can lead to bugs.

3. Appending the Value

    lst.append(val)

Adds the value of val to the end of the list lst.

4. Returning the List

    return lst

Returns the modified list with the new value added.

5. Function Calls & Print

print(add_to(3), add_to(5))

add_to(3): Since no list is passed, lst is None, so a new list is created: [] → [3]. Returns [3].

add_to(5): Again, no list is passed, so a new list is created: [] → [5]. Returns [5].

print([3], [5]) will output:

[3] [5]

Final Output:

[3] [5]

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