Find the set difference of two Numpy arrays or lists

Question

Without converting Numpy arrays to sets, what is the approach to find the set difference of two Numpy arrays or lists?

Answer 1

You can use the setdiff1d() function of Numpy that returns elements in array1 that are not in array2. Here is an example:

>>> import numpy as np
>>> a=np.array([11,12,13,14,15])
>>> b=np.array([14,15,16,17,18])
>>> np.setdiff1d(a, b)
array([11, 12, 13])
>>> np.setdiff1d(b, a)
array([16, 17, 18])