Most efficient way to find mode in numpy array

Check scipy.stats.mode() (inspired by @tom10’s comment):

import numpy as np
from scipy import stats

a = np.array([[1, 3, 4, 2, 2, 7],
              [5, 2, 2, 1, 4, 1],
              [3, 3, 2, 2, 1, 1]])

m = stats.mode(a)
print(m)

Output:

ModeResult(mode=array([[1, 3, 2, 2, 1, 1]]), count=array([[1, 2, 2, 2, 1, 2]]))

As you can see, it returns both the mode as well as the counts. You can select the modes directly via m[0]:

print(m[0])

Output:

[[1 3 2 2 1 1]]