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

To count the number of appearances:

from collections import defaultdict

appearances = defaultdict(int)

for curr in a:
    appearances[curr] += 1

To remove duplicates:

a = set(a)