[Numpy-discussion] behavior of masked arrays
Giorgio F. Gilestro
Fri Mar 7 08:56:59 CST 2008
I have some arrays that sometimes need to have some of their values
masked away or, simply said, not considered during manipulation.
I tried to fulfill my purposes using both NaNs and MaskedArray but
neither of them really helped completely.
Let's give an example:
from numpy import *
a = array(arange(40).reshape(5,8), dtype=float32)
b = array(arange(40,80).reshape(5,8), dtype=float32)
a[1,1] = NaN
tt, ttp = scipy.stats.ttest_ind(a,b,axis=0)
c = numpy.ma.masked_array(a, mask=isnan(a))
tt1, ttp1 = scipy.stats.ttest_ind(c,b,axis=0)
print (ttp == ttp1).all()
will return True.
My understanding is that only a few functions will be able to properly
use MA during execution. Is this correct or am I missing something here?
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