Re: unexpected behavior for ind

Joel,

The whole expression "a.ne.10.or.ismissing(a)" itself contains a
missing value. Print this without ind() around it, and you will see
what I mean.

The ind() function returns indices only where it finds True values,
not False or missing.

The most conservative formulation for what you requested is this:

   ind (where (ismissing (a), True, a.ne.10))

--Dave

Joel Norris wrote:
> I'd like to use "ind" to find data that does not have a particular value
> or is missing, but it unexpectedly does not return the indices of missing
> data.
>
> Here's a short sample script.
>
> Copyright (C) 1995-2009 - All Rights Reserved
> University Corporation for Atmospheric Research
> NCAR Command Language Version 5.1.1
> The use of this software is governed by a License Agreement.
> See http://www.ncl.ucar.edu/ for more details.
> ncl 0> a = (/10,20,30,-999/)
> ncl 1> a@_FillValue = -999
> ncl 2> print(ind(a.ne.10))
> (0) 1
> (1) 2
> ncl 3> print(ind(ismissing(a)))
> (0) 3
> ncl 4> print(ind(a.ne.10.or.ismissing(a)))
> (0) 1
> (1) 2
>
> Why doesn't "ind" return 1, 2, and 3?
>
> Joel
>
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Received on Fri Feb 26 22:03:03 2010