Python – Sort Strings by maximum frequency character

Given a string, the task is to write a Python program to perform sort by maximum occurring character.

Input : test_list = [“geekforgeeks”, “bettered”, “for”, “geeks”] 
Output : [‘for’, ‘geeks’, ‘bettered’, ‘geekforgeeks’] 
Explanation : 1 < 2 < 3 < 4, is ordering of maximum character occurrence frequency.

Input : test_list = [“geekforgeeks”, “for”, “geeks”] 
Output : [‘for’, ‘geeks’, ‘geekforgeeks’] 
Explanation : 1 < 2 < 4, is ordering of maximum character occurrence frequency. 

Method #1 : Using sort() + Counter() + max()

In this, we perform inplace sorting using sort(), and Counter() is used to compute characters frequency, max() used to get maximum of computed frequencies.

Python3

# Python3 code to demonstrate working of
# Sort Strings by maximum frequency character
# Using sort() + Counter() + max()
from collections import Counter

# getting maximum character frequency
def max_freq(arg_str):
    res = Counter(arg_str)
    return arg_str.count(max(res, key = res.get))

# initializing list
test_list = ["geekforgeeks", "bettered", "for", "geeks"]

# printing original list
print("The original list is : " + str(test_list))

# performing sort
test_list.sort(key = max_freq)

# printing result
print("Sorted List : " + str(test_list))

Output:

The original list is : ['geekforgeeks', 'bettered', 'for', 'geeks']
Sorted List : ['for', 'geeks', 'bettered', 'geekforgeeks']

Method #2 : Using sorted() + lambda + Counter()

In this, we perform the task of performing sort using sorted(), and lambda function to get a single statement logical expression, avoiding external function call.

Python3

# Python3 code to demonstrate working of
# Sort Strings by maximum frequency character
# Using sorted() + lambda + Counter()
from collections import Counter

# getting maximum character frequency
def max_freq(arg_str):
    res = Counter(arg_str)
    return arg_str.count(max(arg_str, key = arg_str.get))

# initializing list
test_list = ["geekforgeeks", "bettered", "for", "geeks"]

# printing original list
print("The original list is : " + str(test_list))

# performing sort
# lambda function to drive logic
res = sorted(test_list,
             key = lambda arg_str : arg_str.count(
               max(Counter(arg_str), key = Counter(arg_str).get)))

# printing result
print("Sorted List : " + str(res))

Output:

The original list is : ['geekforgeeks', 'bettered', 'for', 'geeks']
Sorted List : ['for', 'geeks', 'bettered', 'geekforgeeks']

The time and space complexity for all the methods are the same:

Time Complexity: O(n)

Space Complexity: O(n)