That’s such a fun coding project idea! Let’s see how we can approach it.

So basically, you want a function that takes a list of numbers and also what operation to do on each one. Letting the user choose makes it super cool! Here’s how you could tackle this:

First, define your operations clearly:

It’s useful to group your operations neatly. For instance, you could use a Python dictionary (makes it easy to map a user’s choice to your desired operations):

operations = {
    'double': lambda x: x * 2,
    'triple': lambda x: x * 3,
    'square': lambda x: x ** 2,
    'filter_even': lambda nums: [x for x in nums if x % 2 == 0]
}
    

Second, creating the function itself:

You asked if loops or list comprehension were better. Honestly, list comprehensions are pretty neat and clean. Let’s say you don’t need filtering, just simple math operations:

def apply_operation(numbers, operation):
    if operation not in operations:
        return "Oops! You've picked a wrong operation."
    # Special handling if the chosen operation is 'filter_even' since it processes the whole list at once
    if operation == 'filter_even':
        return operations[operation](numbers)
    
    # Use list comprehension for other operations
    return [operations[operation](num) for num in numbers]
    

What happens with invalid inputs?

Yep, good catch! We added that simple “Oops!” message. You could also improve it by telling the user what operations are actually available:

def apply_operation(numbers, operation):
    if operation not in operations:
        valid_ops = ', '.join(operations.keys())
        return f"Oops! '{operation}' isn't valid. Choose from: {valid_ops}"
    if operation == 'filter_even':
        return operations[operation](numbers)
    return [operations[operation](num) for num in numbers]
    

A simple user interface:

Make it easy for the users by showing them the options. Here’s an example of how you could get user input:

nums = [1, 2, 3, 4]
print("Here's your list:", nums)
print("Pick an operation:")
for op in operations:
    print("-", op)

choice = input("What would you like to do?: ")
result = apply_operation(nums, choice)
print("Here's your result:", result)
    

Some beginner-friendly tips:

• Keep it simple: Small functions are easy to debug and read.
• Error-check early: Let the user know right away if something’s not quite right.
• Give clear instructions: Let users know explicitly what operations they can perform.

Hope this helps you get started! You got this, have fun coding! 😊