Python 3 list.pop() vs slice

Question

Given that:

l = [1,2,3,4,5]

What is the difference between l.pop(0) and l = l[1:] if we only consider final state of l?

It seems to me that contents of l should be the same, no matter which option I choose and simple tests seem to show the same, but I have a piece of code which behaves differently based on which operation I use.

I'm using Python 3.6.7 from Anaconda.

EDIT: Code example:

forward = range(10)

backward = forward[::-1]

parts = []

f_p = []

b_p = []

for f, b in zip(forward, backward):

    if len(f_p) == 3:

        parts.append((f_p, b_p))

        f_p = f_p[1:] # f_p.pop(0)

        b_p = b_p[1:] # b_p.pop(0)

    f_p.append(f)

    b_p.append(b)

print(parts)

Why are results different?

Answer 1

The major difference is that l.pop(0) will change the list and remove the first element from it, but, l[1:] will return a new list with all elements from list l except the first one. Slicing will not affect the original list.