count of occurance of elements in array python code example

Example 1: How to count occurences of a certain item in a numpy array

>>> import numpy as np
>>> y = np.array([1, 2, 2, 2, 2, 0, 2, 3, 3, 3, 0, 0, 2, 2, 0])

>>> np.count_nonzero(y == 1)
1
>>> np.count_nonzero(y == 2)
7
>>> np.count_nonzero(y == 3)
3

Example 2: python count occurrences of an item in a list

>>> [1, 2, 3, 4, 1, 4, 1].count(1)
3