[Numpy-discussion] None as missing value
Pierre GM
pgmdevlist at mailcan.com
Mon Jul 3 01:01:30 CDT 2006
Keith,
> > Is there something better than None to represent missing values so
> > that when I convert to numpy arrays (actually matrices) I'll be all
> > set? (I could use -99, but that would be even more embarrassing than
> > my python skills.)
As Tim suggested, have a look at the masked array module. However, the result
will NOT be exportable to matrices, unless you fill the missing value first
(for example, with -99 ;)). I use MaskedArrays a lot, they're quite flexible.
An alternative would be to use nan instead of None:
>>> import numpy as N
>>> x = [[1, nan], [2, 3]]
>>> print N.matrix(x)
[[ 1. nan]
[ 2. 3. ]]
Of course, the solution will depend on what you need...
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