[Numpy-discussion] quickselect

josef.pktd at gmail.com josef.pktd at gmail.com
Wed May 29 00:12:11 EDT 2013

On Tue, May 28, 2013 at 6:31 PM, Charles R Harris
<charlesr.harris at gmail.com> wrote:
> Hi All,
> There is a PR adding quickselect to numpy as a function `partition`.
> Comments on name and exposure in the numpy API are welcome.

I think the name is fine. It's possible to get used to it.

One possible use I can think of is if I want to sort afterwards only
one of the tails (like largest 15%).


medium: like percentiles it would be nice to partition into more than
two sets, if that can be done more efficiently than calling the
function twice.

it won't work to calculate the median or other quantiles since those interpolate
np.median: "When N is even, it is the average of the two middle values
of V_sorted"

AFAICS based on the docstring (I closed my eyes when the c code scrolled by)


> Chuck
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