[Numpy-discussion] isnan() equivalent for np.NaT?

[Scott Sanderson]

Hi All,

I'm working on upgrading Zipline (github.com/quantopian/zipline) to the
latest numpy, and I'm getting a FutureWarnings about the upcoming change in
the behavior of comparisons on np.NaT. I'd like to be able to do checks
for NaT in a way that's forwards-compatible, but I couldn't find a function
analogous to `np.isnan` for NaT. Am I missing something that already
exists? If not, is there interest in such a function? I'd like to be able
to pre-emptively fix the warnings in Zipline so that we're ready when the
change actually happens, but it doesn't seem like the necessary tools are
available right now.

-Scott

[Gerrit Holl]

Post by Scott Sanderson
I'm working on upgrading Zipline (github.com/quantopian/zipline) to the
latest numpy, and I'm getting a FutureWarnings about the upcoming change in
the behavior of comparisons on np.NaT. I'd like to be able to do checks for
NaT in a way that's forwards-compatible, but I couldn't find a function
analogous to `np.isnan` for NaT. Am I missing something that already
exists? If not, is there interest in such a function? I'd like to be able
to pre-emptively fix the warnings in Zipline so that we're ready when the
change actually happens, but it doesn't seem like the necessary tools are
available right now.

Hi Scott,

see https://github.com/numpy/numpy/issues/5610

Gerrit.

[Stephan Hoyer]

Agreed -- this would be really nice to have. For now, the best you can do
is something like the following:


def is_na(x):
x = np.asarray(x)
if np.issubdtype(x.dtype, (np.datetime64, np.timedelta64)): # ugh
int_min = np.iinfo(np.int64).min
return x.view('int64') == int_min
else:
return np.isnan(x)

Post by Gerrit Holl

Post by Scott Sanderson
I'm working on upgrading Zipline (github.com/quantopian/zipline) to the
latest numpy, and I'm getting a FutureWarnings about the upcoming change

in

Post by Scott Sanderson
the behavior of comparisons on np.NaT. I'd like to be able to do checks

for

Post by Scott Sanderson
NaT in a way that's forwards-compatible, but I couldn't find a function
analogous to `np.isnan` for NaT. Am I missing something that already
exists? If not, is there interest in such a function? I'd like to be

able

Post by Scott Sanderson
to pre-emptively fix the warnings in Zipline so that we're ready when the
change actually happens, but it doesn't seem like the necessary tools are
available right now.

Hi Scott,
see https://github.com/numpy/numpy/issues/5610
Gerrit.
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