PYTHON

how to get frequency of each elements in a python list

# easiest way to count the frequency of all elements in a list
lst = ['Sam', 'Sam', 'Tim', 'Tim', 'Tim', 'r', 'l']

freq = {} # stores the frequency of elements
counting = [freq.update({x: lst.count(x)}) for x in lst]

# output of freq 
{'Sam': 2, 'Tim': 3, 'r': 1, 'l': 1}

#credit: buggyprogrammer.com
#Note: if you print "counting" it will return a list full of None so ignore it. 

find frequency of numbers in list python

from collections import Counter

def frequency_table(n):
    table = Counter(n)
    print('Number	Frequency')
    for number in table.most_common() :
        print('{0}	{1}'.format(number[0], number[1]))
        
# src : Doing Math With Python

Count Frequency of elements in array using python

def countFreq(arr):
    visited = [False for _ in range(len(arr))]
    
    for i in range(len(arr)):
        count = 1
        if visited[i]:
            continue
        for j in range(i+1, len(arr)):
            if arr[i] == arr[j]:
                count += 1
                visited[j] = True
        visited[i] = True
        print(f'{arr[i]} : {count}')

# Time complexity: O(n * n)
# space complexity: O(n)