palindrome iteration

MRAB python at mrabarnett.plus.com
Fri Aug 27 22:14:44 CEST 2010


On 27/08/2010 20:43, Jussi Piitulainen wrote:
> Dave Angel writes:
>
>> Jussi Piitulainen wrote:
>>> Ian writes:
>>>> Of course, the simpler way is to use the definition of a
>>>> Palindrome as the same backwards and forwards.
>>>>
>>>> def isPalindrome(pal)
>>>>       return pal == pal.reverse
>>>
>>> Agreed. But is there any nicer way to spell .reverse than [::-1] in
>>> Python? There is .swapcase() but no .reverse(), right?
>>>
>> There can't be a .reverse() method on string, because it's
>> immutable. You could use
>>
>>      "".join(reversed(pal))
>>
>> but I'd prefer  pal[::-1]  as I said earlier.
>
> There could easily be a .reverse() method on strings. It would return
> the reversed string, like .swapcase() returns the swapcased string.

Lists have a .reverse method, but it's an in-place reversal. In order
to reduce confusion, a string method which returned the string reversed
would be better called .reversed().



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