John Hunter wrote: > On Fri, Jul 18, 2008 at 2:49 PM, Andrew Straw <[EMAIL PROTECTED]> wrote: > >> I just spent a little time getting hexbin to discard nans without >> failing in mysterious ways. >> >> I'm sending 2 patches: one will detect nans and raise a suitable >> exception. The other will automatically drop the nans and continue with >> hexbin. The 2nd seems a little nicer in functionality, but the code is a >> little more convoluted and hence more brittle, and so I'm torn as to >> which I'd prefer. (The problem with just detecting nans from the >> beginning is that it would cause an extra pass through the data in all >> cases.) >> > > I think the nans should be dropped with no raise or warning, which is > consistent with our handling elsewhere. I don't think your approach, > which if I am reading this correctly assumes that is x or y has nans > then the min or max will be nan, is correct. Eg, > > In [51]: x = np.random.rand(10) > > In [52]: x[4] = np.nan > > In [53]: x.min() > Out[53]: 0.37072898459621617 > > In [54]: x.max() > Out[54]: 0.79367039009185769 > > > I think min and max in the presence of nans is undefined. True -- that slipped past me, since in my use case the nans were always coming out for both min and max... > But you can > just pay for the extra pass > > mask = np.isnan(x) & np.isnan(y) > if mask.any(): > # mask where If you're happy with that extra cost, I'll modify axes.delete_masked_points() so that hexbin and scatter are automatically filtered in this way. Given the speed complaints we sometimes get, I was hesitant to add another pass through the data.
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