How do I check if a numpy dtype is integral?

Question

How do I check if a numpy dtype is integral? I tried:

issubclass(np.int64, numbers.Integral)

but it gives False.

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Update: it now gives True.

Answer 1

Numpy has a hierarchy of dtypes similar to a class hierarchy (the scalar types actually have a bona fide class hierarchy that mirrors the dtype hierarchy). You can use np.issubdtype(some_dtype, np.integer) to test if a dtype is an integer dtype. Note that like most dtype-consuming functions, np.issubdtype() will convert its arguments to dtypes, so anything that can make a dtype via the np.dtype() constructor can be used.

http://docs.scipy.org/doc/numpy/reference/arrays.dtypes.html#specifying-and-constructing-data-types

>>> import numpy as np
>>> np.issubdtype(np.int32, np.integer)
True
>>> np.issubdtype(np.float32, np.integer)
False
>>> np.issubdtype(np.complex64, np.integer)
False
>>> np.issubdtype(np.uint8, np.integer)
True
>>> np.issubdtype(np.bool, np.integer)
False
>>> np.issubdtype(np.void, np.integer)
False

In a future version of numpy, we will make sure that the scalar types are registered with the appropriate numbers ABCs.