On Wed, Jan 11, 2012 at 7:05 AM, Neal Becker <ndbecker2@gmail.com> wrote:

Michael Hull wrote:

...

Hi Everyone, First off, thanks for all your hard work on numpy, its a really great help! I was wondering if there was a standard 'groupby' in numpy, that similar to that in itertools. I know its not hard to write with np.diff, but I have found myself writing it on more than a couple of occasions, and wondered if  there was a 'standarised' version I was missing out on?? Thanks,

Mike

I've played with groupby in pandas.

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I agree (unsurprisingly) that pandas is your best bet: http://pandas.sourceforge.net/groupby.html I've had it on my TODO list to extend the pandas groupby engine (which has grown fairly sophisticated) to work with generic ndarrays and record arrays: https://github.com/wesm/pandas/issues/123 It shouldn't actually be that hard for most simple cases. I could imagine the results of a groupby being somewhat difficult to interpret without axis labeling/indexing, though. cheers, Wes