compare two numpy array

Question

I am trying to compare two 1d numpy arrays for mismatch as follows. I have this working with partial success.

import numpy as np
a= np.array([0,1,2,3,4,13])
b= np.array([0,1,2,3,4,10,11,12])
mis = max( np.sum(~np.isin(b,a)), np.sum(~np.isin(a,b)))
print(mis)

output: 3

expected output : 4 ( 13,10,11,12 are mismatches)

Answer 1

Why are you taking the max of the two sums instead of adding the sums? You are only grabbing the missing entries from a single array (the larger one) by doing that, when you clearly want both.

mis = np.sum(~np.isin(b,a)) + np.sum(~np.isin(a,b))

Answer 2

Your code would work if you add the np.sum:

mis = np.sum(~np.isin(b,a)) + np.sum(~np.isin(a,b))

However, check out setxor1d:

np.setxor1d(a,b) 
# out 
# array([10, 11, 12, 13])

You can easily get the length then.