How to check if two strings are anagrams in Python

Strings are a vastly used data type in Python to store all kinds of text data: characters, alphabets, numbers, and alphanumeric. They are immutable; however, we can use different methods to manipulate them to achieve the desired results.

What are anagram strings?

Two strings are said to be anagrams if they have the same frequency of each character, which means we can obtain the other string upon rearranging one string.

For example, STUDY and DUSTY are anagrams because they have the same length, and each character in STUDY has a corresponding equal character in DUSTY. On the other hand STING and NIGHT are not anagrams despite having the same length because S and H have no corresponding equal characters.

def checkAnagram(string1 , string2):
    
    print('String 1 : ' + string1)
    print('String 2 : ' + string2)
    #convert the strings to lowercase
    string1 = string1.lower()
    string2 = string2.lower()
    #check if length is same
    if(len(string1) != len(string2)):
        print('\nNot Anagram\n')
    else:
        #sort the strings
        sortString1 = sorted(string1)
        sortString2 = sorted(string2)
        #check if same
        if(sortString1 == sortString2):
          print('\nAre Anagram\n')
        else:
          print('\nNot Anagram\n')
string1 = "Study"
string2 = "Dusty" 
checkAnagram(string1 , string2)
string3 = "Sting"
string4 = "Night" 
checkAnagram(string3 , string4)

Code explanation

Line 1: Define the checkAnagram() function that takes two strings as parameters and prints if they are anagrams or not.
Lines 3–4: Print both the strings on the console.
Lines 7–8: Use the built-in lower() function to convert all characters to lowercase because Python is a case-sensitive language.
Line 11: Use the len() built-in function to get the length of each string and compare using the != operator. If different lengths, print 'Not Anagram'.
Lines 16–17: Use the sorted() built-in function to arrange the characters of each string in ascending order.
Line 20: Compare both sorted strings and check if they are the same using the == operator. If same, print 'Are Anagram'; else, print 'Not Anagram'.
Line 28: Call the checkAnagram() function for string1 and string2 and the output, in this case, will be 'Are Anagram'.
Line 32: Call the checkAnagram() function for string3 and string4 and the output, in this case, will be 'Not Anagram'.

Using a list and dictionary

In this method, we convert the strings in a list and save each character and its frequency in a dictionary object. The values in the dictionary against each unique key are used to check if strings are anagrams.

def checkAnagram(string1 , string2):
    
    print('String 1 : ' + string1)
    print('String 2 : ' + string2)
    #convert the strings to lowercase
    string1 = string1.lower()
    string2 = string2.lower()
    #convert strings to lists
    list1 = list(string1)
    list2 = list(string2)
 
    #create a dictionary
    count = {}
 
    #save char frequency as values against each char
    for char in list1:
        if char not in count:
            count[char] = 0
        count[char] += 1
 
    for char in list2:
        if char not in count:
            print('\nNot Anagram\n')
            break
        count[char] -= 1
 
    else:
        #Check if dictionary empty
        for c in count.values():
            if c != 0:
               print('\nNot Anagram\n')
               break
        else:
           print('\nAre Anagram\n')
string1 = "Study"
string2 = "Dusty" 
checkAnagram(string1 , string2)
string3 = "Sting"
string4 = "Night" 
checkAnagram(string3 , string4)

Code explanation

Line 1: Define the checkAnagram() function that takes two strings as parameters and prints if they are anagrams.
Lines 3–4: Print both the strings on the console.
Lines 7–8: Use built-in lower() function to convert all characters to lowercase because Python is a case-sensitive language.
Lines 11–12: Convert both the strings to a list and assign them to list1 and list2 variables, respectively.
Line 15: Create a count dictionary to store each character as a key and its frequency as a value.
Lines 18–21: Loop through list1, create a key for each unique character in the string and increment the value by 1 if the same character appears again.
Lines 23–27: Loop through list2, check for the key against each character in the string and decrement the value by 1 if the key is found; else, print 'Not Anagram'.
Lines 31–36: Loop through the values in the count dictionary, and check if the value against any key is not zero. If found not equal to zero, print 'Not Anagram'; else, print 'Are Anagram'.
Line 41: Call the checkAnagram() function for string1 and string2 and the output, in this case, will be 'Are Anagram'.
Line 45: Call the checkAnagram() function for string3 and string4 and the output, in this case, will be 'Not Anagram'.

Free Resources

Method	Time Complexity	Space Complexity
Using sorted() function	O(nlogn)	O(1)
Using list and dictionary	O(n)	O(n)

How to check if two strings are anagrams in Python

What are anagram strings?

Using `sorted()` function

Code explanation

Using a list and dictionary

Code explanation

Comparing methods

Test your understanding

How to check if two strings are anagrams in Python

What are anagram strings?

Using sorted() function

Code explanation

Using a list and dictionary

Code explanation

Comparing methods

Test your understanding

Using `sorted()` function