How to count the frequency of the elements in an unordered list?

Question

I need to find the frequency of elements in an unordered list

a = [1,1,1,1,2,2,2,2,3,3,4,5,5]

output->

b =         


        

Answer 1

from collections import OrderedDict
a = [1,1,1,1,2,2,2,2,3,3,4,5,5]
def get_count(lists):
    dictionary = OrderedDict()
    for val in lists:
        dictionary.setdefault(val,[]).append(1)
    return [sum(val) for val in dictionary.values()]
print(get_count(a))
>>>[4, 4, 2, 1, 2]

To remove duplicates and Maintain order:

list(dict.fromkeys(get_count(a)))
>>>[4, 2, 1]