Immutable sequence types lacking index() method

Jp Calderone exarkun at divmod.com
Tue Aug 31 21:21:53 CEST 2004


Anne Wangnick wrote:
> Dear all,
> 
> I don't get why the index() method is only defined for mutable sequence
> types. This is not what I expected. Shouldn't this be added in Python? Is
> there such a PEP already?

   For all the *intended* uses of tuples, you should already know all 
the indexes you need to know.  They are implicit in the use of a tuple 
as a data structure.  If you do *not* know the index, you probably 
should be using a list instead.

   There have been numerous discussiong about what the *real* 
differences between tuples and lists are, both here and on python-dev. 
I recommend searching the archives if you are interested in the details.

   Jp



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