Anagram Program in Python

Introduction

In this tutorial, we'll delve deep into the intriguing world of anagram program in Python, shedding light on their significance in linguistics and their fascinating role in programming. As you navigate through, you'll understand how Python's extensive libraries and methods make detecting anagrams not only efficient but also enlightening.

Overview

An anagram, at its core, is about rearranging the letters of one string to form another. But when it comes to programming, it's more than mere rearrangement. Python, known for its adaptability, offers multiple avenues for anagram detection. This tutorial will guide you through the underlying theory of the anagram program in Python, along with its specific approaches.

What is Anagram in Python?

An anagram is a captivating linguistic construct, essentially a word or phrase that's formulated by judiciously rearranging the letters of a different word or phrase. This rearrangement necessitates that each of the original letters is utilized once and only once. Historically, these anagrams have been embedded deeply within various facets of culture. Literary giants have often utilized them to inject layers of meaning or cryptic messages into their works. On a similar note, cryptographers have employed anagrams as tools for encoding, thus adding an extra layer of secrecy to messages.

One might find amusement in everyday examples too: consider how the word 'listen' can undergo a transformation to give us 'silent', or how 'cinema' can be artistically shuffled to yield 'iceman'. Shifting our focus to the programming world, anagrams hold a special place. Coding assessments, especially those aiming to evaluate a candidate's problem-solving prowess, recurrently pose the challenge of detecting anagrams. It's a brilliant way to ascertain one's capability to think algorithmically and efficiently.

Python, a high-level programming language celebrated for its readability and robustness, comes to the fore when dealing with such challenges. Its extensive library, brimming with string and list operations, becomes instrumental in simplifying the process of verifying anagrams. The underlying principle for discerning true anagrams is straightforward yet crucial: they should encompass the exact set of characters, and the occurrence frequency of each character should be consistent, irrespective of their placement.

Programs to Check if Two Strings are Anagrams in Python

Let us check out some anagram code in Python to understand hands-on anagram meaning in Python.

Method #1: Using sorted() function

Code:

def are_anagrams(str1, str2):
    sorted_str1 = sorted(str1)
    sorted_str2 = sorted(str2)
    return sorted_str1 == sorted_str2

# Input strings
string1 = "listen"
string2 = "silent"

if are_anagrams(string1, string2):
    print(f"{string1} and {string2} are anagrams.")
else:
    print(f"{string1} and {string2} are not anagrams.")

Explanation:

• The are_anagrams function takes two input parameters: str1 and str2.
• Inside the function, it sorts the characters in both str1 and str2 using the sorted function. This creates new lists, sorted_str1 and sorted_str2, containing the characters of the input strings sorted in alphabetical order.
• The function then compares the sorted lists sorted_str1 and sorted_str2. If they are equal, it means that the input strings have the same characters and the same frequency of each character, which is a characteristic of anagrams. In this case, the function returns True.
• If the sorted lists are not equal, the function returns False, indicating that the input strings are not anagrams.

Method #2 : Using Counter() function

Code:

from collections import Counter

def are_anagrams(str1, str2):
    return Counter(str1) == Counter(str2)

# Input strings
string1 = "listen"
string2 = "silent"

if are_anagrams(string1, string2):
    print(f"{string1} and {string2} are anagrams.")
else:
    print(f"{string1} and {string2} are not anagrams.")

Explanation:

• The are_anagrams function takes two input parameters: str1 and str2.
• Inside the function, it creates two Counter objects, counter_str1 and counter_str2, using the Counter constructor. Each Counter object counts the occurrences of characters in the respective input strings str1 and str2.
• The function then compares the two Counter objects using the equality operator (==). If the two Counter objects are equal, it means that the input strings have the same characters and the same frequency of each character, which is a characteristic of anagrams. In this case, the function returns True.
• If the Counter objects are not equal, the function returns False, indicating that the input strings are not anagrams.

Method #3: Using inbuilt list and Sort() Methods

Code:

def are_anagrams(str1, str2):
    # Convert strings to lists of characters and sort them
    sorted_str1 = sorted(list(str1))
    sorted_str2 = sorted(list(str2))
    
    return sorted_str1 == sorted_str2

# Input strings
string1 = "listen"
string2 = "silent"

if are_anagrams(string1, string2):
    print(f"{string1} and {string2} are anagrams.")
else:
    print(f"{string1} and {string2} are not anagrams.")

Explanation:

• The are_anagrams function takes two input parameters: str1 and str2.
• Inside the function, both input strings str1 and str2 are converted into lists of characters using the list function. Then, these character lists are sorted using the sorted function. This step ensures that the characters in both input strings are ordered in alphabetical order.
• The sorted character lists sorted_str1 and sorted_str2 are then compared using the equality operator (==). If the two lists are equal, it means that the characters in the input strings are the same, just arranged in a different order. This is a characteristic of anagrams. In this case, the function returns True.
• If the sorted character lists are not equal, the function returns False, indicating that the input strings are not anagrams. This is an example of anagram in Python list.

More Anagram Program in Python Examples

i) Using sorted() function

Code:

def are_anagrams(str1, str2):
    return sorted(str1) == sorted(str2)

# Input strings
string1 = input("Enter the first string: ")
string2 = input("Enter the second string: ")

if are_anagrams(string1, string2):
    print(f"{string1} and {string2} are anagrams.")
else:
    print(f"{string1} and {string2} are not anagrams.")

Explanation:

• The are_anagrams function remains unchanged and checks whether two input strings are anagrams of each other by comparing the sorted versions of the strings.
• The code now prompts the user to enter two strings. It uses the input function to take user input for both string1 and string2.
• After receiving the input strings, the code calls the are_anagrams function, passing the input strings as arguments, to determine if they are anagrams.
• Depending on the result of the anagram check, the code prints either that the input strings are anagrams or that they are not anagrams.

ii) By counting characters

Code:

def are_anagrams(str1, str2):
    # Remove spaces and convert to lowercase
    str1 = str1.replace(" ", "").lower()
    str2 = str2.replace(" ", "").lower()

    # Check if lengths are equal
    if len(str1) != len(str2):
        return False

    # Count character occurrences in both strings
    char_count = [0] * 256  # Assuming ASCII characters
    for char in str1:
        char_count[ord(char)] += 1

    for char in str2:
        char_count[ord(char)] -= 1
        if char_count[ord(char)] < 0:
            return False

    return True

# Input strings
string1 = input("Enter the first string: ")
string2 = input("Enter the second string: ")

if are_anagrams(string1, string2):
    print(f"{string1} and {string2} are anagrams.")
else:
    print(f"{string1} and {string2} are not anagrams.")

Explanation:

• The are_anagrams function first removes spaces and converts both input strings str1 and str2 to lowercase using the replace and lower methods. This step helps in treating the strings in a case-insensitive manner and ignoring spaces.
• The function checks whether the lengths of the two modified strings are equal. If they are not, it immediately returns False, as strings with different lengths cannot be anagrams.
• It initializes a list called char_count with 256 elements. This list is used to count the occurrences of characters in the ASCII character set. Each element corresponds to the ASCII value of a character.
• The code then iterates through each character in str1 and increments the count for that character's ASCII value in the char_count list.
• Similarly, it iterates through each character in str2 and decrements the count for that character's ASCII value in the char_count list. If at any point the count goes below 0, it means that there are more occurrences of that character in str2 than in str1, so the function immediately returns False.
• If both strings have the same counts of characters, the function returns True, indicating that the input strings are anagrams.
• The code then prompts the user to input two strings. It uses the input function to take user input for both string1 and string2.
• The code calls the are_anagrams function, passing the input strings as arguments, and determines if they are anagrams.
• Depending on the result of the anagram check, the code prints either that the input strings are anagrams or that they are not anagrams.

iii) By Counter() function

Code:

from collections import Counter

def are_anagrams(str1, str2):
    return Counter(str1) == Counter(str2)

# Input strings
string1 = "listen"
string2 = "silent"

if are_anagrams(string1, string2):
    print(f"{string1} and {string2} are anagrams.")
else:
    print(f"{string1} and {string2} are not anagrams.")

Explanation:

• The are_anagrams function takes two input parameters: str1 and str2.
• Inside the function, it uses the Counter class from the collections module to create two Counter objects: counter_str1 and counter_str2. These objects count the occurrences of each character in the input strings str1 and str2, respectively.
• The function then compares the two Counter objects using the equality operator (==). If the two Counter objects are equal, it means that the input strings have the same characters and the same frequency of each character, which is a characteristic of anagrams. In this case, the function returns True.
• If the Counter objects are not equal, the function returns False, indicating that the input strings are not anagrams.
• The code then demonstrates the use of the are_anagrams function by providing two predefined strings, "listen" and "silent", and calling the function to check if they are anagrams. If they are indeed anagrams, it prints that fact; otherwise, it prints that they are not anagrams.

iv) Reverse anagram check

Code:

def is_reverse_anagram(str1, str2):
    return str1 == str2[::-1]

# Input strings
string1 = input("Enter the first string: ")
string2 = input("Enter the second string: ")

if is_reverse_anagram(string1, string2):
    print(f"{string1} is the reverse anagram of {string2}.")
else:
    print(f"{string1} is not the reverse anagram of {string2}.")

Explanation:

• The is reverse_anagram function takes two input parameters: str1 and str2.
• Inside the function, it compares str1 with the reverse of str2 using slicing with a step of -1 (str2[::-1]). This effectively reverses the order of the characters in str2.
• If str1 and the reversed str2 are equal, it means that the characters in str1 are the same as the characters in str2, but in reverse order. This is the condition for a "reverse anagram." In this case, the function returns True.
• If the comparison does not result in equality, the function returns False, indicating that the input strings are not "reverse anagrams."
• The code then prompts the user to input two strings. It uses the input function to take user input for both string1 and string2.
• The code calls the is_reverse_anagram function, passing the input strings as arguments, and determines if they meet the criteria for a reverse anagram.
• Depending on the result of the reverse anagram check, the code prints either that the first string is the reverse anagram of the second string or that it is not.

v) Using position verification technique

Code:

def are_anagrams(str1, str2):
    # Remove spaces and convert to lowercase
    str1 = str1.replace(" ", "").lower()
    str2 = str2.replace(" ", "").lower()

    # Check if lengths are equal
    if len(str1) != len(str2):
        return False

    # Initialize a dictionary to store character counts
    char_count = {}

    # Count characters in str1
    for char in str1:
        if char in char_count:
            char_count[char] += 1
        else:
            char_count[char] = 1

    # Verify characters in str2
    for char in str2:
        if char in char_count:
            char_count[char] -= 1
        else:
            return False

    # Verify that all character counts are zero
    for count in char_count.values():
        if count != 0:
            return False

    return True

# Input strings
string1 = input("Enter the first string: ")
string2 = input("Enter the second string: ")

if are_anagrams(string1, string2):
    print(f"{string1} and {string2} are anagrams.")
else:
    print(f"{string1} and {string2} are not anagrams.")

Conclusion

The journey of understanding anagrams in Python showcases the beauty of combining linguistic concepts with algorithmic challenges. With the guidance provided here, any professional can seamlessly detect anagrams in Python.

Beyond this, for those dedicated learners aspiring to ascend further in their Python journey or delve into other cutting-edge technologies, upGrad offers courses that pave the way for expertise. Don't just stop here; let your quest for knowledge propel you forward.

FAQs

1. Do anagrams have practical applications outside of games and challenges?

Certainly. Anagrams have historically been used in cryptography, especially in creating certain types of codes and puzzles. In the realm of programming, it hones logic and string manipulation skills.

2. Are there performance differences between the various Python methods for detecting anagrams?

Yes. While the sorting method is straightforward, it might not be the most efficient for larger strings. Using dictionaries or frequency counts can be more efficient in such scenarios.

3. Is the concept of anagrams limited to the English language?

No, the idea of anagrams is universal and can be applied to words in any language, provided the language's characters can be rearranged to form meaningful new words or phrases.

4. How can I extend the anagram game in Python for more complexity?

Introducing time limits, multi-level challenges, or using phrases instead of single words can add layers of complexity to an anagram game.

5. Are there any Python libraries specifically built for anagram-related tasks?

While Python doesn't have a dedicated library for anagrams, its rich set of string and list methods are often sufficient. However, third-party libraries might offer specialized functions.

6. How to check if two strings are anagrams in Python?

In Python, check if two strings are anagrams by comparing their sorted versions after stripping spaces and converting them to lowercase. If they match, they're anagrams. Use: sorted(str1.replace(" ", "").lower()) == sorted(str2.replace(" ", "").lower()).