count the number of multiple instances in a list python code example

Example 1: How to see how many times somting is in a list python

vowels = ['a', 'e', 'i', 'o', 'i', 'u']
count = vowels.count('i')

Example 2: count occurrence in array python

arr = np.array( [1, 2, 3, 2, 1, 2])
occ = np.count_nonzero(arr==0)
print(occ)
0
occ = np.count_nonzero(arr==1)
print(occ)
2