NumPy provides base classes that you can/should use for subtype-checking, rather than the Python types.
Use np.integer to check for any instance of either signed or unsigned integers.
Use np.signedinteger and np.unsignedinteger to check for signed types or unsigned types.
>>> np.issubdtype(np.uint32, np.integer)
True
>>> np.issubdtype(np.uint32, np.signedinteger)
False
>>> np.issubdtype(int, np.integer)
True
>>> np.issubdtype(np.array([1, 2, 3]).dtype, np.integer)
True
All floating or complex number types will return False when tested.
np.issubdtype(np.uint*, int) will always be False because the Python int is a signed type.
A useful reference showing the relationship between all of these base classes is found in the documentation here.
