from math import ceil, sqrt

import sys

if sys.version_info[0] == 2:

from itertools import izip_longest as zip_longest

else:

from itertools import zip_longest

def cipher_text(plain_text):

plain_text = _cleanse(plain_text)

square_size = int(ceil(sqrt(len(plain_text))))

square = _chunks_of(plain_text, square_size)

return ' '.join([''.join(column)

for column in zip_longest(*square, fillvalue=' ')])

def _cleanse(text):

"""Lowercase a string and remove punctuation and whitespace

"""

return ''.join([character for character in text

if character.isalnum()]).lower()

def _chunks_of(text, num):

if len(text) <= num:

return [text]

return [text[:num]] + _chunks_of(text[num:], num)