.remove() from a list - request for explanation

[bowlofred]

Don't modify an iterator while you're iterating over it. Some options are to loop over a copy of the list or to just copy the data you do want rather than delete the data you don't.

l = [1, 2, 3, 2, 2, 2, 1]
    for el in l[:]:  # loops over a copy of l.  Modifying l doesn't change the loop iterator.
    ...

l = [1, 2, 3, 2, 2, 2, 1]
l = [e for e in if l != 2]  # list comprehension copies the data we want directly