[Numpy-discussion] numpy datetime64 NaT string conversion bug & patch

[Charles G. Waldman]

If you convert an array of strings to datetime64s and 'NaT' (or one of
its variants) appears in the string, all subsequent values are
rendered as NaT:

(this is in 1.7.1 but the problem is present in current dev version as well)

>>> import numpy as np
>>> a = np.array(['2010', 'nat', '2030'])
>>> a.astype(np.datetime64)
array(['2010', 'NaT', 'NaT'], dtype='datetime64[Y]')

The fix is to re-initalize 'dt' inside the loop in
_strided_to_strided_string_to_datetime
(patch attached)



Correct behavior (with patch):
>>> import numpy as np
>>> a=np.array(['2010', 'nat', '2020'])
>>> a.astype(np.datetime64)
array(['2010', 'NaT', '2020'], dtype='datetime64[Y]')
>>>
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