a query on sorting
Steve Holden
steve at holdenweb.com
Thu Sep 28 03:18:13 EDT 2006
Paul McGuire wrote:
> "Steve Holden" <steve at holdenweb.com> wrote in message
> news:mailman.796.1159357863.10491.python-list at python.org...
> <snip>
>
> >>> [x for x in enumerate(a)]
> [(0, 9), (1, 4), (2, 3), (3, 5), (4, 2), (5, 6), (6, 7), (7, 1), (8, 2)]
>
>
> Just curious, Steve, but why do this list comprehension when:
>
> list(enumerate(a))
>
> works just as well?
>
Dumb stupidity would account for that. Knowing that enumerate(a) was an
iterator I simply used the first iterative context that came to mind.
List is somewhat more effective.
> In the interests of beating a dead horse into the ground (metaphor-mixing?),
> I looked at using map to one-line the OP's request, and found an interesting
> inconsistency.
>
> I tried using map(reversed, list(enumerate(a))), but got back a list of
> iterators. To create the list of tuples, I have to call the tuple
> constructor on each one, as in:
>
> map(tuple,map(reversed,list(enumerate(a))))
>
> However, sorted returns a list, not a listsortediterator. Why the
> difference in these two builtins?
>
Ask the developers. Beats me ...
> I guess you can beat a dead horse into the ground, but you can't make him
> drink.
>
I guess. Thanks for flogging this horse so effectively.
regards
Steve
--
Steve Holden +44 150 684 7255 +1 800 494 3119
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