[Numpy-discussion] argsort question (original) (raw)
Travis Oliphant oliphant.travis at ieee.org
Thu Jun 8 11:15:38 EDT 2006
- Previous message (by thread): [Numpy-discussion] argsort question
- Next message (by thread): [Numpy-discussion] argsort question
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Robert Cimrman wrote:
Hi all,
I have just lost some time to find a bug related to the fact, that argsort does not preserve the order of an array that is already sorted, see the example below. For me, it would be sufficient to mention this fact in the docstring, although having order preserving argsort is also an option :). What do the developers think? In [33]:a = nm.zeros( 10000 ) In [34]:b = nm.arange( 10000 ) In [35]:nm.alltrue( nm.argsort( a ) == b ) Out[35]:False
You want a "stable" sorting algorithm like the "mergesort". Use the argsort method with the mergesoret kind option:
a.argsort(kind='merge')
-Travis
- Previous message (by thread): [Numpy-discussion] argsort question
- Next message (by thread): [Numpy-discussion] argsort question
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]