python count occurrences of each unique item in list code example

Example 1: python count number of unique elements in a list

# Basic syntax:
len(set(my_list))
# By definition, sets only contain unique elements, so when the list
# is converted to a set all duplicates are removed. 

# Example usage:
my_list = ['so', 'so', 'so', 'many', 'duplicated', 'words']
len(set(my_list))
--> 4

# Note, list(set(my_list)) is a useful way to return a list containing
#	only the unique elements in my_list

Example 2: how to find no of times a elements in list python

thislist = (1, 3, 7, 8, 7, 5, 4, 6, 8, 5)

x = thislist.count(5)

print(x)

Example 3: how to find the number of times a number appears in python

dict((i, a.count(i)) for i in a)

Example 4: 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

Example 5: python count occurrences of an item in a list

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