Python | Count the Number of matching characters in a pair of string Last Updated : 11 Jul, 2025 Comments Improve Suggest changes Like Article Like Report The problem is about finding how many characters are the same in two strings. We compare the strings and count the common characters between them. In this article, we'll look at different ways to solve this problem.Using Set Sets are collections of unique items, so by converting both strings into sets, we can easily find the common characters between them. This method is efficient because sets quickly identify matches.Example: Python s1 = "VISHAKSHI" s2 = "VANSHIKA" # find common characters res= len(set(s1.lower()).intersection(set(s2.lower()))) print(res) Output6 Explanation:s1.lower() and s2.lower() converts both strings to lowercase to ensure case-insensitivity.set(s1.lower()) and set(s2.lower()) converts the strings to sets, removing duplicate characters.intersection() finds common characters between the two sets.len() counts the number of common characters.Using Counter Counter that helps to count how many times each item appears in a list or string. It's useful for tasks like finding out how many characters are shared between two strings.Example: Python from collections import Counter s1 = "VISHAKSHI" s2 = "VANSHIKA" # Count characters c1 = Counter(s1.lower()) c2= Counter(s2.lower()) # Find common characters and sum their counts res = sum((c1 & c2).values()) print(res) Output6 Explanation:Counter(s1.lower()) and Counter(s2.lower()) counts the frequency of each character in both strings.c1 & c2 finds the common characters between the two strings, keeping the minimum frequency.sum((c1 & c2).values()) sums the frequencies of the common characters.Using List ComprehensionThis method checks which characters are found in both strings by turning them into sets. It then counts how many characters are the same in both strings. Python s1 = "VISHAKSHI" s2 = "VANSHIKA" # Find common characters res= len([char for char in set(s1.lower()) if char in set(s2.lower())]) print(res) Output6 Explanation:set(string1.lower()) and set(string2.lower()) converts both strings to lowercase and then into sets to remove duplicates and ensure case-insensitive comparison.list comprehension find characters that appear in both sets.len() counts the number of common characters. Comment More infoAdvertise with us Next Article Python program to check if a string contains all unique characters A AashutoshChauhan Follow Improve Article Tags : Misc Python python-string Python string-programs python +1 More Practice Tags : Miscpythonpython Similar Reads Count the number of Unique Characters in a String in Python We are given a string, and our task is to find the number of unique characters in it. For example, if the string is "hello world", the unique characters are {h, e, l, o, w, r, d}, so the output should be 8.Using setSet in Python is an unordered collection of unique elements automatically removing du 2 min read Count Occurrences of a Character in String in Python We are given a string, and our task is to count how many times a specific character appears in it using Python. This can be done using methods like .count(), loops, or collections.Counter. For example, in the string "banana", using "banana".count('a') will return 3 since the letter 'a' appears three 2 min read Count Occurrences of a Character in String in Python We are given a string, and our task is to count how many times a specific character appears in it using Python. This can be done using methods like .count(), loops, or collections.Counter. For example, in the string "banana", using "banana".count('a') will return 3 since the letter 'a' appears three 2 min read Python program to check if a string contains all unique characters To implement an algorithm to determine if a string contains all unique characters. Examples: Input : s = "abcd" Output: True "abcd" doesn't contain any duplicates. Hence the output is True. Input : s = "abbd" Output: False "abbd" contains duplicates. Hence the output is False. One solution is to cre 3 min read Python program to check if a string contains all unique characters To implement an algorithm to determine if a string contains all unique characters. Examples: Input : s = "abcd" Output: True "abcd" doesn't contain any duplicates. Hence the output is True. Input : s = "abbd" Output: False "abbd" contains duplicates. Hence the output is False. One solution is to cre 3 min read Find all duplicate characters in string in Python In this article, we will explore various methods to find all duplicate characters in string. The simplest approach is by using a loop with dictionary.Using Loop with DictionaryWe can use a for loop to find duplicate characters efficiently. First we count the occurrences of each character by iteratin 2 min read Like