palindrome iteration

[MRAB]

On 29/08/2010 21:34, Roy Smith wrote:
> In article<8dunm7Fv5nU1 at mid.individual.net>,
>   Gregory Ewing<greg.ewing at canterbury.ac.nz>  wrote:
>
>> Steven D'Aprano wrote:
>>>   I'm not entirely sure what the use-case for swapcase is.
>>
>> Obviously it's for correcting things that were typed
>> in with tHE cAPS lOCK kEY oN bY mISTAKE. :-)
>
> So it would seem (http://bugs.python.org/msg94026).
>
> It's also useful for when you're looking for a crypto algorithm and
> rot13 is too strong.
>
> It also provides a handy way to write is_alpha()...
>
> def is_alpha(c):
>      return abs(ord(c) - ord(c.swapcase())) == 32
>
> print is_alpha('a')
> print is_alpha('A')
> print is_alpha('1')
> print is_alpha('>')

How is that better than:

print 'a'.isalpha()
print 'A'.isalpha()
print '1'.isalpha()
print '>'.isalpha()