Now I know that it is not safe to modify the list during an iterative looping. However, suppose I have a list of strings, and I want to strip the strings themselves. Does replacement of mutable values count as modification?
It's considered poor form. Use a list comprehension instead, with slice assignment if you need to retain existing references to the list.
a = [1, 3, 5] b = a a[:] = [x + 2 for x in a] print b