[Python-ideas] add a list.swap() method

Terry Reedy tjreedy at udel.edu
Fri Jun 26 22:41:30 CEST 2009

Raymond Hettinger wrote:
> [Kristján Valur Jónsson]
>> In particular, append(), pop() and insert() modify the list length, 
>> which might confuse some subclasses.
> These are all part of the most basic functions of list.

I have to chuckle a bit at that statement.

When I posted the proposal to add .pop() (before there were formal 
'PEP's), a couple of people accused my of trying to ruin Python.

So agree, even if they did not, and I am glad you think so too ;-)

 > A subclasser should know that.
> They are different from swap() which is an optimization hack that breaks 
> encapsulation and is not a basic function of lists.  The docs are fine as-is.
> Adding esoterica to the docs tends to make the docs harder to digest
> and less useful to people trying to learn the language.

As someone who hopes to be introducing Python to new people, I 
appreciate that you keep digestibility in mind, even if I occasionally 
forget in the quest for technical accuracy (which is also important).

Terry Jan Reedy

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