>>> import numpy as np
>>> a = np.arange(10)
>>> a
array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
>>> b = np.array([ 1, 2, 3, 4, np.nan, 6, 7, 8, 9, 10])
>>> b
array([ 1., 2., 3., 4., nan, 6., 7., 8., 9., 10.])
>>> c = [ not np.isnan(i) for i in b]
>>> c
[True, True, True, True, False, True, True, True, True, True]
>>> d = [i for i,j in zip(a,c) if j]
>>> d
[0, 1, 2, 3, 5, 6, 7, 8, 9]