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

Data. Let's say we have a list:

fruits = ['banana', 'banana', 'apple', 'banana']

Solution. Then we can find out how many of each fruit we have in the list by doing this:

import numpy as np    
(unique, counts) = np.unique(fruits, return_counts=True)
{x:y for x,y in zip(unique, counts)}

Output:

{'banana': 3, 'apple': 1}