Find top K frequent elements from a list of tuples in Python

We have a list of tuples. In it we are required to find the top k frequent element. If k is 3 we are required to find the top three elements from the tuples inside the list.

With defaultdict

We put the the elements into a dictionary container using defaultdict. Then find out only the elements which satisfy that top k conditions.

Example

 Live Demo

import collections from operator import itemgetter from itertools import chain # Input list initialization listA = [[('Mon', 126)], [('Tue', 768)],[('Wed', 512)], [('Thu', 13)],[('Fri', 341)]] # set K K = 3 #Given list print("Given list:\n",listA) print("Check value:\n",K) # Using defaultdict dict_ = collections.defaultdict(list) new_list = list(chain.from_iterable(listA)) for elem in new_list:    dict_[elem[0]].append(elem[1]) res = {k: sum(v) for k, v in dict_.items()} # Using sorted res = sorted(res.items(), key=itemgetter(1), reverse=True)[0:K] # Output print("Top 3 elements are:\n", res)

Output

Running the above code gives us the following result −

Given list: [[('Mon', 126)], [('Tue', 768)], [('Wed', 512)], [('Thu', 13)], [('Fri', 341)]] Check value: 3 Top 3 elements are: [('Tue', 768), ('Wed', 512), ('Fri', 341)]

With sorted and itergetter

In this approach we use the itemgetter function but apply it within the sorted function by mentioning the range from 0 to K.

Example

 Live Demo

from operator import itemgetter from itertools import chain # Input list initialization listA = [[('Mon', 126)], [('Tue', 768)],[('Wed', 512)], [('Thu', 13)],[('Fri', 341)]] # set K K = 3 #Given list print("Given list:\n",listA) print("Check value:\n",K) # Using sorted res = sorted(list(chain.from_iterable(listA)),    key = itemgetter(1), reverse = True)[0:K] # Output print("Top 3 elements are:\n", res)

Output

Running the above code gives us the following result −

Given list: [[('Mon', 126)], [('Tue', 768)], [('Wed', 512)], [('Thu', 13)], [('Fri', 341)]] Check value: 3 Top 3 elements are: [('Tue', 768), ('Wed', 512), ('Fri', 341)]