01.numpy中判断None和nan方法

import numpy as np
from numpy import NaN
>>> print(type(None))

>>> print(type(NAN))

>>> import numpy as np
>>> a = np.array([1,2,3,None])
>>> a[a != np.array(None)]
array([1, 2, 3], dtype=object)
>>> from numpy import NaN
>>> b = np.array([1,2,3,NaN])
>>> b[~np.isnan(b)]
array([1., 2., 3.])