Python:リストまたはarrayで要素の位置を特定し、要素の個数を計算する

import numpy as np

a = np.array([1,2,2,3,3,4,4,5,5,5,5])
b = [1,2,2,3,3,4,4,5,5,5,5]
print(type(a))
print(type(b))

# list       
set_a = set(a)
set_b = set(b)


print("---list           ---")
for ele in set_b:
    print("  {}    ：{}".format(ele,b.count(ele)))
print("---list             ---")
for ele in set_b:
    print("  {}    ：{}".format(ele,b.index(ele)))

print("---nparray           ---")
for ele in set_a:
    print("  {}    ：{}".format(ele,np.sum(a == ele)))
print("---nparray             ---")
for ele in set_a:
    print("  {}    ：{}".format(ele,np.where(a == ele)))