On Mon, 28 Jul 2008 23:41:51 -0700, iu2 wrote: > On Jul 29, 3:59 am, John Machin <[EMAIL PROTECTED]> wrote: >> On Jul 29, 8:10 am, John Krukoff <[EMAIL PROTECTED]> 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 ...- Hide quoted >> text - >> >> - Show quoted text - > > I think it is wrong, using this on my data returns the wrong result > data = [108, 58, 68, 108] >>>> [x[1] for x in sorted(zip(data, xrange(len(data))))] > [1, 2, 0, 3]
It looked wrong to me at first, but I think this is correct. The two largest numbers were at positions 0 and 3. They come last in the result. 58 is the smallest, and was at position 1, which is the first in the result. ** Posted from http://www.teranews.com ** -- http://mail.python.org/mailman/listinfo/python-list
