understanding “item for item in list_a if …” PYTHON

Question

I\'ve seen the following code many times, and I know it\'s the solution to my problems, but I\'m really struggling to understand HOW it works. The code in particular is:

Answer 1

You are building a list by looping through(and filtering) another list

The first item is the thing you are putting into your result list

You can also do stuff to the element such as

[i*2 for i in range(6)]

The output will be:

 [0, 2, 4, 6, 8, 10]

Essentially the first "item" lets you control what you put into your result list