2011/10/14 Matthew Brett <[email protected]> > Hi, > > On Fri, Oct 14, 2011 at 4:33 AM, Chao YUE <[email protected]> wrote: > > Dear all, > > > > is there any difference between np.nan, np.NaN and np.NAN? they really > > confuse me.... > > they are all Not a Number? > > > > In [75]: np.nan==np.NaN > > Out[75]: False > > > > In [77]: np.NaN==np.NAN > > Out[77]: False > > The nan value is not equal to itself: > > In [70]: np.nan == np.nan > Out[70]: False > > See: > > http://en.wikipedia.org/wiki/NaN > > But: > > In [71]: np.isnan(np.nan) > Out[71]: True > > In [72]: np.isnan(np.NAN) > Out[72]: True > > In [73]: np.isnan(np.NaN) > Out[73]: True > > Best, > > Matthew >
Also on my computer: >>> numpy.nan is numpy.NAN True >>> numpy.nan is numpy.NaN True So they really are the same. But you shouldn't rely on this (always use numpy.isnan to test for nan-ness). -=- Olivier
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