How to iterate over some characters in a string and the others will stay as it is. ?

[ThomasL]

You should have a look at the module itertools
It has a lot of very useful functions included

from itertools import product

one = ["one","o","n","e"]
two = ["two","t","w","o"]

for first, second in product(one, two):
    print(f'{first} and {second}')