calculator in python using match case

Yulia Chive

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·

07-12-2024

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Building a Python Calculator with match-case

Python's match-case statement (introduced in Python 3.10) provides a powerful and elegant way to handle conditional logic. This article demonstrates how to leverage match-case to create a flexible and readable calculator. We'll build a calculator that can handle basic arithmetic operations (+, -, *, /) and provide user-friendly error handling.

Understanding match-case

Before diving into the calculator, let's briefly review the match-case syntax. It allows us to match a subject expression against multiple patterns. If a pattern matches, the corresponding code block is executed.

match expression:
    case pattern1:
        # Code block 1
    case pattern2:
        # Code block 2
    case _:  # Default case (optional)
        # Code block for unmatched expressions

Building the Calculator

Our calculator will take two numbers and an operator as input from the user. The match-case statement will determine the appropriate operation to perform.

def calculator():
    """Performs basic arithmetic operations using match-case."""
    try:
        num1 = float(input("Enter the first number: "))
        num2 = float(input("Enter the second number: "))
        operator = input("Enter the operator (+, -, *, /): ")

        match operator:
            case "+":
                result = num1 + num2
                print(f"Result: {num1} + {num2} = {result}")
            case "-":
                result = num1 - num2
                print(f"Result: {num1} - {num2} = {result}")
            case "*":
                result = num1 * num2
                print(f"Result: {num1} * {num2} = {result}")
            case "/":
                if num2 == 0:
                    print("Error: Division by zero!")
                else:
                    result = num1 / num2
                    print(f"Result: {num1} / {num2} = {result}")
            case _:
                print("Invalid operator!")

    except ValueError:
        print("Invalid input. Please enter numbers only.")
    except Exception as e:
        print(f"An unexpected error occurred: {e}")


if __name__ == "__main__":
    calculator()

This code first prompts the user for two numbers and an operator. The try-except block handles potential ValueError exceptions (if the user enters non-numeric input) and other unexpected errors. The match-case statement then elegantly handles the different arithmetic operations. Notice the specific handling of division by zero. The default case (case _) catches invalid operator inputs.

Extending the Calculator

This is a basic example. We can easily extend this calculator to include more advanced features:

• More Operators: Add support for modulo (%), exponentiation (**), etc.
• Input Validation: Implement more robust input validation to handle various edge cases.
• Functions: Incorporate more complex mathematical functions (e.g., square root, sine, cosine).
• GUI: Create a graphical user interface (GUI) using libraries like Tkinter or PyQt for a more user-friendly experience.

Conclusion

The match-case statement provides a concise and readable way to implement a calculator in Python. Its pattern-matching capabilities make it easy to handle different operations and error conditions. This example demonstrates a fundamental application, offering a solid foundation for building more sophisticated calculators with added features and functionalities. The clear structure and error handling improve the overall robustness and usability of the code.