[Numpy-discussion] 1D array sorting ascending and descending by fields

Benjamin Root ben.root at ou.edu
Mon Jun 4 20:17:13 EDT 2012

On Monday, June 4, 2012, Chris Barker wrote:

> On Mon, Jun 4, 2012 at 11:10 AM, Patrick Redmond <plredmond at gmail.com<javascript:;>>
> wrote:
> > Here's how I sorted primarily by field 'a' descending and secondarily by
> > field 'b' ascending:
> could you multiply the numeric field by -1, sort, then put it back --
> somethign like:
> data *- -1
> data_sorted = np.sort(data, order=['a','b'])
> data_sorted *= -1
> (reverse if necessary -- I lost track...)
> -Chris

While that may work for this users case, that would not work for all
dtypes. Some, such as timedelta, datetime and strings would not be able to
be multiplied by a number.

Would be an interesting feature to add, but I am not certain if the
negative sign notation would be best. Is it possible for a named field to
start with a negative sign?

Ben Root
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