Example 1: collections.counter in python
>>> from collections import Counter
>>>
>>> myList = [1,1,2,3,4,5,3,2,3,4,2,1,2,3]
>>> print Counter(myList)
Counter({2: 4, 3: 4, 1: 3, 4: 2, 5: 1})
>>>
>>> print Counter(myList).items()
[(1, 3), (2, 4), (3, 4), (4, 2), (5, 1)]
>>>
>>> print Counter(myList).keys()
[1, 2, 3, 4, 5]
>>>
>>> print Counter(myList).values()
[3, 4, 4, 2, 1]
Example 2: python counter
>>> Counter('abracadabra').most_common(3)
[('a', 5), ('r', 2), ('b', 2)]
Example 3: collections counter
# importing the collections module
import collections
# intializing the arr
arr = [1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3]
# getting the elements frequencies using Counter class
elements_count = collections.Counter(arr)
# printing the element and the frequency
for key, value in elements_count.items():
print(f"{key}: {value}")
Example 4: python counter
sum(c.values()) # total of all counts
c.clear() # reset all counts
list(c) # list unique elements
set(c) # convert to a set
dict(c) # convert to a regular dictionary
c.items() # convert to a list of (elem, cnt) pairs
Counter(dict(list_of_pairs)) # convert from a list of (elem, cnt) pairs
c.most_common()[:-n-1:-1] # n least common elements
c += Counter() # remove zero and negative counts