[Numpy-discussion] comparing arrays with NaN in them.
Christopher Barker
Chris.Barker@noaa....
Thu Aug 23 19:34:20 CDT 2007
Hi all,
I was just trying to write a unit test for something where I was
expecting to get some NaN's in the array. However, since NaN == NaN
returns false, the simple test:
assert(alltrue(a == b))
>>> a = N.array((1,2,3,N.nan))
>>> b = N.array((1,2,3,N.nan))
>>> a == b
array([ True, True, True, False], dtype=bool)
>>> assert(N.alltrue(a == b))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AssertionError
>>>
So is there any way to test is two arrays are the same, when there may
be a NaN or two mixed in???
With a bit of thought -- this works:
>>> N.alltrue(a[~N.isnan(a)] == b[~N.isnan(b)])
True
but that feels like a kludge. maybe some sort of "TheseArrays are binary
equal" would be useful.
-CHB
--
Christopher Barker, Ph.D.
Oceanographer
Emergency Response Division
NOAA/NOS/OR&R (206) 526-6959 voice
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Chris.Barker@noaa.gov
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