List rotation

[Sion Arrowsmith]

M. Clift <noone at here.com> wrote:
>I can think of the long/wrong way to do it as shown for trans = 3, but there
>must be some simpler idea.
>
>
>for idx in range(len(items)):
>    if list[idx:idx + 1] == ['a']:
>       list[idx:idx + 1] = ['d']
>    if list[idx:idx + 1] == ['b']:
>       list[idx:idx + 1] = ['a']

Depending on what the possible characters are, you might be able
to do something with chr() and ord() and modulo arithmetic:

c2 = chr((ord(c1) - ord('a') + n) % 4 + ord('a'))

but Peter Otten's solution is more general.

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