Have two lists - for any whitespace in list 1, move element down in list 2 to match without removing-CodePudding

Need help on Vigenere cipher to generate the key from the keyword, looking to do this very simply after cyclical rotation to get the keyword the same len as message:

message = "i love my horse"

keyword = "mare"

list1 = ['i', ' ', 'l', 'o', 'v', 'e', ' ', 'm', 'y', ' ', 'h', 'o', 'r', 's', 'e']

list2 = ['m', 'a', 'r', 'e', 'm', 'a', 'r', 'e', 'm', 'a', 'r', 'e', 'm', 'a', 'r']

How can I match up the spacing of list 1 by moving index 1 of list 2 down without taking out the "a"? In other words, how can I push "right" every element of list 2 based on list 1 without removing the element itself?

Appreciate any help! Thank you so much!

CodePudding user response：

You can use itertools.cycle to generate the letters of the keyword repeatedly with the help of a list comprehension:

message = "i love my horse"
keyword = "mare"

from itertools import cycle

c = cycle(keyword)
list2 = [' ' if l == ' ' else next(c) for l in message]

Output:

['m', ' ', 'a', 'r', 'e', 'm', ' ', 'a', 'r', ' ', 'e', 'm', 'a', 'r', 'e']