[Numpy-discussion] type checking, what's recommended?

[josef.pktd at gmail.com]

If I want to know whether something that might be an array is really a
plain ndarray and not a subclass, is using `type` the safest bet?

All the other forms don't discriminate against subclasses.

>>> type(np.ma.zeros(3)) is np.ndarray
False
>>> type(np.zeros(3)) is np.ndarray
True

>>> isinstance(np.ma.zeros(3), np.ndarray)
True
>>> isinstance(np.zeros(3), np.ndarray)
True

>>> issubclass(np.ma.zeros(3).__class__, np.ndarray)
True
>>> issubclass(np.zeros(3).__class__, np.ndarray)
True

>>> isinstance(np.matrix(np.zeros(3)), np.ndarray)
True
>>> type(np.matrix(np.zeros(3))) is np.ndarray
False

Thanks,

Josef