Short rot13 function

Question

Hi there!

I am searching for an short and cool rot13 function in Python ;-) I've written this function:

def rot13(s):
    chars = "abcdefghijklmnopqrstuvwxyz"
    trans = chars[13:]+chars[:13]
    rot_char = lambda c: trans[chars.find(c)] if chars.find(c)>-1 else c
    return ''.join( rot_char(c) for c in s ) 

Can anyone make it better? E.g supporting uppercase characters.

This is less a question, than having fun to find a short Python function ;-)

Answer 1

>>> 'foobar'.encode('rot13')
'sbbone'

(I've heard rumors this doesn't work in Python 3.x though.)

Answer 2

Try this:

import codecs
codecs.encode("text to be rot13()'ed", "rot13")

Answer 3

The maketrans and translate functions in the string module are handy for this type of thing. Of course, the encode method in Amber's response is even handier for this specific case.

Here's a general solution:

import string

def make_rot_n(n):
 lc = string.lowercase
 trans = string.maketrans(lc, lc[n:] + lc[:n])
 return lambda s: string.translate(s, trans)

rot13 = make_rot_n(13)

rot13('foobar')
# 'sbbone'

Answer 4

Here's a maketrans/translate solution

import string #fixed typo was using
rot13 = string.maketrans( \
    "ABCDEFGHIJKLMabcdefghijklmNOPQRSTUVWXYZnopqrstuvwxyz", \
    "NOPQRSTUVWXYZnopqrstuvwxyzABCDEFGHIJKLMabcdefghijklm")
string.translate("Hello World!", rot13)
# 'Uryyb Jbeyq!'

Answer 5

its very simple

import codecs
codecs.encode('foobar', 'rot13')
>> 'sbbone'

Answer 6

/usr/lib/python/this.py

def rot13(s):
    d = {}
    for c in (65, 97):
        for i in range(26):
            d[chr(i+c)] = chr((i+13) % 26 + c)
    return "".join([d.get(c, c) for c in s])