Switch input text layout

switch_layout.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import sys
import codecs

DVORAK =  ur"§[]',.pyfgcrl/=aoeuidhtns-\`;qjkxbmwvz" ur'±!@#$%^&*(){}"<>PYFGCRL?+AOEUIDHTNS_|~:QJKXBMWVZ'
RUSSIAN = ur"ё-=йцукенгшщзхъфывапролджэ\]ячсмитьбю." ur'Ё!"№;%:?*()_+ЙЦУКЕНГШЩЗХЪФЫВАПРОЛДЖЭ/[ЯЧСМИТЬБЮ,'

LAYOUTS = (DVORAK, RUSSIAN)


def translate(char, frm, to):
    index = frm.find(char)
    if index >= 0:
        return to[index]


def occurrence(chars, text):
    return sum(char in chars for char in text)


def translate_line(line):
    idx, line_layout = max(enumerate(LAYOUTS), key=lambda (i, layout): occurrence(layout, line))
    next_layout = LAYOUTS[(idx + 1) % len(LAYOUTS)]
    return ''.join(translate(char, line_layout, next_layout) or char for char in line)

if __name__ == '__main__':
    arg = u' '.join(a.decode('utf-8') for a in sys.argv[1:])
    lines = [arg] if arg else codecs.getreader('utf-8')(sys.stdin)
    print ''.join(translate_line(line).encode('utf-8') for line in lines),