seemingly simple list indexing problem

[John Machin]

On Jul 29, 8:10 am, John Krukoff <jkruk... at ltgc.com> wrote:
> On Mon, 2008-07-28 at 16:24 -0500, Ervan Ensis wrote:
> > My programming skills are pretty rusty and I'm just learning Python so
> > this problem is giving me trouble.
>
> > I have a list like [108, 58, 68].  I want to return the sorted indices
> > of these items in the same order as the original list.  So I should
> > return [2, 0, 1]
>
> > For a list that's already in order, I'll just return the indices, i.e.
> > [56, 66, 76] should return [0, 1, 2]
>
> > Any help would be appreciated.
>
> > --
> >http://mail.python.org/mailman/listinfo/python-list
>
> If your lists aren't so large that memory is an issue, this might be a
> good place for a variation of decorate, sort, undecorate.
>
> >>> listToSort = [ 108, 58, 68 ]
> >>> decorated = [ ( data, index ) for index, data in
>
> enumerate( listToSort ) ]>>> decorated
>
> [(108, 0), (58, 1), (68, 2)]>>> result = [ None, ] * len( listToSort )
> >>> for sortedIndex, ( ignoredValue, originalIndex ) in
>
> enumerate( sorted( decorated ) ):
> ...     result[ originalIndex ] = sortedIndex
> ...>>> result
>
> [2, 0, 1]
>

Simpliciter:

>>> data = [99, 88, 77, 88, 66]
>>> [x[1] for x in sorted(zip(data, xrange(len(data))))]
[4, 2, 1, 3, 0]
>>>

Use case? Think data == database table, result == index ...