Python: Find the string similarity between two given strings

Last update on June 12 2025 12:41:34 (UTC/GMT +8 hours)

Find similarity between two strings.

Write a Python program to find string similarity between two given strings.

From Wikipedia:
In computer science, approximate string matching (often colloquially referred to as fuzzy string searching) is the technique of finding strings that match a pattern approximately (rather than exactly).

Sample Solution:

Python Code:

# Import the difflib module for computing string similarity
import difflib

# Define a function to calculate the similarity ratio between two strings
def string_similarity(str1, str2):
    # Create a SequenceMatcher object with the lowercase versions of the input strings
    result = difflib.SequenceMatcher(a=str1.lower(), b=str2.lower())
    
    # Return the similarity ratio between the two strings
    return result.ratio()

# Initialize two strings for comparison
str1 = 'Python Exercises'
str2 = 'Python Exercises'

# Print the original strings
print("Original string:")
print(str1)
print(str2)

# Print a message indicating the similarity between the two strings
print("Similarity between two said strings:")
print(string_similarity(str1, str2))

# Repeat the process with different pairs of strings
str1 = 'Python Exercises'
str2 = 'Python Exercise'
print("\nOriginal string:")
print(str1)
print(str2)
print("Similarity between two said strings:")
print(string_similarity(str1, str2))

str1 = 'Python Exercises'
str2 = 'Python Ex.'
print("\nOriginal string:")
print(str1)
print(str2)
print("Similarity between two said strings:")
print(string_similarity(str1, str2))

str1 = 'Python Exercises'
str2 = 'Python'
print("\nOriginal string:")
print(str1)
print(str2)
print("Similarity between two said strings:")
print(string_similarity(str1, str2))

str1 = 'Python Exercises'
str2 = 'Java Exercises'
print("\nOriginal string:")
print(str1)
print(str2)
print("Similarity between two said strings:")
print(string_similarity(str1, str2))

Sample Output:

Original string:
Python Exercises
Python Exercises
Similarity between two said strings:
1.0

Original string:
Python Exercises
Python Exercise
Similarity between two said strings:
0.967741935483871

Original string:
Python Exercises
Python Ex.
Similarity between two said strings:
0.6923076923076923

Original string:
Python Exercises
Python
Similarity between two said strings:
0.5454545454545454

Original string:
Java Exercises
Python
Similarity between two said strings:
0.0

Flowchart:

Flowchart: Find the string similarity between two given strings.

For more Practice: Solve these Related Problems:

Write a Python program to calculate the similarity ratio between two strings using the SequenceMatcher from difflib.
Write a Python program to implement a function that returns a similarity score between 0 and 1 for two input strings.
Write a Python program to compare two strings and output their similarity percentage based on matching characters and order.
Write a Python program to use a custom algorithm to compute the edit distance and derive a similarity metric between two strings.

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