Comparing two numpy arrays and removing elements

Question

I have been going through several solutions, but I am not able to find a solution I need.

I have two numpy arrays. Let\'s take a small example<

Answer 1

If you really do have numpy arrays then you can use numpy.setdiff1d as below

import numpy as np

x = np.array([1,2,3,4,5,6,7,8,9])
y = np.array([3,4,5])

z = np.setdiff1d(x, y)
# array([1, 2, 6, 7, 8, 9])

Answer 2

You can use built-in sets:

final_x = set(x) - set(y)

and subtract the second from the first. You can convert final_x to a list or numpy.array if you feel so inclined.

Answer 3

Simply pass the negated version of boolean array returned by np.in1d to array x:

>>> x = np.array([1,2,3,4,5,6,7,8,9])
>>> y = [3,4,5]
>>> x[~np.in1d(x, y)]
array([1, 2, 6, 7, 8, 9])