Inconsistent results when using a for loop with list comprehensions in Python 3.9
I'm optimizing some code but I've been banging my head against this for hours. I'm working with an scenario with a for loop that seems to be producing inconsistent results when used alongside list comprehensions. I have the following code snippet that processes a list of integers and should filter out even numbers while doubling the odd ones: ```python numbers = [1, 2, 3, 4, 5, 6] result = [] for num in numbers: # Using a list comprehension to generate the new list result += [num * 2 for num in numbers if num % 2 != 0] ``` I expected `result` to be `[2, 6, 10]`, as it should double only the odd numbers from the original list, but instead, I am getting `[2, 6, 10, 2, 6, 10]`. I have tried breaking it into two separate steps: first filtering the odd numbers and then doubling them: ```python odd_numbers = [num for num in numbers if num % 2 != 0] result = [num * 2 for num in odd_numbers] ``` This approach gives me the expected output, but I'm wondering why the first loop didn't work as intended. Is there a question with the way I'm using list comprehensions inside the for loop? I'm using Python 3.9, and I want to understand the underlying behavior better. Any insights on why this happens and how to fix it while keeping the loop structure? How would you solve this? How would you solve this? Any advice would be much appreciated.