Incrementing letters

[Duncan Booth]

Dan Sommers wrote:

> Wolfram Kraus <kraus at hagen-partner.de> wrote:
> 
>> Duncan Booth wrote:
> 
>>>>>> import string
>>>>>> upone = string.maketrans(
>>> 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
>>> 'bcdefghijklmnopqrstuvwxyzaBCDEFGHIJKLMNOPQRSTUVWXYZA')
>>> 
>>>>>> string.translate("I've got a string s....", upone)
> 
>>> "J'wf hpu b tusjoh t...."
> 
>>> Note the difference though: the Python code does what you said you
>>> wanted, whereas your sample code corrupts punctuation.
> 
>> Wow, that's quite nice. You really learn something new every day :-) A
>> minor improvement: Use string.ascii_letters as the first parameter for
>> string.maketrans

Yes, my first attempt at responding did that, but I changed it because that 
makes the assumption that string.ascii_letters is in a specific order (did 
you know that lowercase came first and uppercase second without checking?)

> 
> And use string.ascii_letters[ 1 : ] + string.ascii_letters[ 0 ] for the
> second parameter to string.maketrans.
> 
Bzzt. Wrong answer. Look closely at the middle of the string.

I did have:

>>> upone = string.maketrans(string.ascii_letters,
    'z'+string.ascii_lowercase[:-1] +
    'Z' + string.ascii_uppercase[:-1])

but as I said, that makes too many assumptions for my liking about the 
contents of those variables.