Caesar's Cipher using python, could use a little help

I like kaizer.se's answer, but I think I can simplify it using the string.maketrans function:

import string

first = raw_input("Please enter Plaintext to Cipher: ")
k = int(raw_input("Please enter the shift: "))

shifted_lowercase = ascii_lowercase[k:] + ascii_lowercase[:k]

translation_table = maketrans(ascii_lowercase, shifted_lowercase)

print first.translate(translation_table)

This code should work pretty well. It also handles arbitrary offsets, including negative.

phrase = raw_input("Please enter plaintext to Cipher: ")
shift = int(raw_input("Please enter shift: "))

result = ''
for char in phrase:
    x = ord(char)

    if char.isalpha():
        x = x + shift

        offset = 65
        if char.islower():
            offset = 97

        while x < offset:
            x += 26

        while x > offset+25:
            x -= 26

        result += chr(x)

print result

The other way to do it, with a slightly different cipher, is simply rotate through all characters, upper and lower, or even all ascii > 0x20.

phrase = raw_input("Please enter plaintext to Cipher: ")
shift = int(raw_input("Please enter shift: "))

result = ''
for char in phrase:
    x = ord(char)

    x = x + shift

    while x < 32:
        x += 96

    while x > 127:
        x -= 96

    result += chr(x)

print result

Put a comma after each print statement; it will still put a space between the characters, but they'll all be on the same line. If you need to print them without the spaces, build them all into a single string and print that at the end.

Here is a different method to show how we can handle this in a very clean way. We define an input alphabet and an output alphabet, then a translation table and use unicode.translate() to do the actual encryption.

import string
# Blatantly steal Lennart's UI design
first = unicode(raw_input("Please enter Plaintext to Cipher: "), "UTF-8")
k = int(raw_input("Please enter the shift: "))

in_alphabet = unicode(string.ascii_lowercase)
out_alphabet = in_alphabet[k:] + in_alphabet[:k]

translation_table = dict((ord(ic), oc) for ic, oc in zip(in_alphabet, out_alphabet))

print first.translate(translation_table)

It can be extended to uppercase letters as needed.