np.unique 使用例

import numpy as np

A = np.array([3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 40, 50])
key, cnt = np.unique(A, return_counts = True)

print(key)
print(cnt)

[ 1  2  3  4  5  6  9 40 50]
[2 1 2 1 3 1 1 1 1]

for k,c in zip(key,cnt):
    print(k,c)

1 2
2 1
3 2
4 1
5 3
6 1
9 1
40 1
50 1