INTERVIEW QUESTION - Find out common letters between two strings Using Python

Introduction

In this tutorial, we will learn how to find common letters between two strings using Python. This task is a common interview question that helps assess your problem-solving skills and understanding of string manipulation. By the end of this guide, you'll be able to implement a solution and understand the underlying concepts.

Step 1: Set Up Your Environment

Before you start coding, ensure you have Python installed on your machine. You can download it from the official Python website. Use an IDE or a code editor such as PyCharm, VSCode, or even Jupyter Notebook for writing your code.

Step 2: Define the Problem

Identify the two strings for which you want to find common letters. You can use hardcoded strings or take input from the user. Here’s a simple example:

string1 = "apple"
string2 = "grape"

Step 3: Convert Strings to Sets

To find common letters easily, convert both strings into sets. Sets automatically handle duplicate values and allow for efficient operations to find intersections.

set1 = set(string1)
set2 = set(string2)

Step 4: Find Common Letters

Use the intersection method of sets to find common letters. This method returns a new set containing elements that are in both sets.

common_letters = set1.intersection(set2)

Step 5: Display the Results

Convert the resulting set back to a string or list if you want to display it neatly. You can use the join method for strings.

result = ''.join(common_letters)
print("Common letters:", result)

Step 6: Complete Code Example

Here’s the complete code snippet that combines all the steps:

# Step 1: Define the strings
string1 = "apple"
string2 = "grape"

# Step 2: Convert strings to sets
set1 = set(string1)
set2 = set(string2)

# Step 3: Find common letters
common_letters = set1.intersection(set2)

# Step 4: Display the results
result = ''.join(common_letters)
print("Common letters:", result)

Conclusion

In this tutorial, you learned how to find common letters between two strings in Python using set operations. This method is not only efficient but also elegant. As next steps, you could explore variations, such as finding common letters in multiple strings or counting the frequency of each common letter. For further practice, consider implementing additional string manipulation tasks or exploring Python's built-in functions for string handling.