Python code examples and curiosities

Welcome to the Python code examples section!

 
Python is a versatile and beginner-friendly programming language widely used for web development, data analysis, artificial intelligence, automation, and more. In this section, you will find practical examples of Python code that cover essential programming concepts such as variables, loops, conditionals, functions, and data structures.

Each example includes a clear explanation to help you understand how the code works and how you can apply it to your own projects. Feel free to modify the examples and experiment with different approaches — that's the best way to learn!

Let's dive into the world of Python programming!

Python Calculator Code Explanation

This Python code implements a basic calculator that allows the user to perform addition, subtraction, multiplication, and division. Here’s a step-by-step explanation of how the code works:

1. Display Options – The code starts by displaying a menu with available operations (addition, subtraction, multiplication, and division).

2. User Input – The user is prompted to enter two numbers and select an operation.

3. Conditional Statements – Based on the selected operation, the code uses if-elif-else statements to perform the corresponding calculation:

   • + – Adds the two numbers.

   • - – Subtracts the second number from the first.

   • * – Multiplies the two numbers.

   • / – Divides the first number by the second (if the second number is not zero).

4. Result Display – The result is printed on the screen.

5. Error Handling – The code handles division by zero and invalid inputs by displaying an error message.

Calculator in Python

def add(a, b):

    return a + b

def subtract(a, b):

    return a - b

def multiply(a, b):

    return a * b

def divide(a, b):

    if b != 0:

        return a / b

    else:

        return "Error: Division by zero is not allowed."

def calculator():

    print(" Simple Calculator")

    print("Choose an operation:")

    print("1 - Add")

    print("2 - Subtract")

    print("3 - Multiply")

    print("4 - Divide")

    choice = input("Enter the number of the desired operation: ")

    if choice in ('1', '2', '3', '4'):

        num1 = float(input("Enter the first number: "))

        num2 = float(input("Enter the second number: "))

        if choice == '1':

            print(f"{num1} + {num2} = {add(num1, num2)}")

        elif choice == '2':

            print(f"{num1} - {num2} = {subtract(num1, num2)}")

        elif choice == '3':

            print(f"{num1} × {num2} = {multiply(num1, num2)}")

        elif choice == '4':

            result = divide(num1, num2)

            print(f"{num1} ÷ {num2} = {result}")

    else:

        print("❌ Invalid option! Please try again.")

if __name__ == "__main__":

    calculator()

How It Works:

• The input() function captures user input as a string.
   

• The float() function converts input values to floating-point numbers.
   

• The if-elif-else structure checks the selected operation and performs the calculation.
   

• If the user tries to divide by zero, the code displays an error message to prevent a crash.

How the Python Calculator Code Works

This Python code implements a simple calculator that performs basic operations like addition, subtraction, multiplication, and division. Here's a detailed explanation to make it clear and easy to follow:

Purpose of Each Function and Structure

Explain why each function and structure is used:

• input() → Captures user input as a string.

• float() → Converts user input into floating-point numbers to allow decimal calculations.

• if-elif-else → Handles user choice and determines which operation to perform.

Error Handling and Input Validation

Explain how the code handles invalid input and prevents crashes:

• Validates that the chosen operation is among the available options.

• Checks for division by zero to avoid runtime errors.

• Handles invalid input (like letters or symbols) gracefully using try-except.

Example of improved error handling:

try:

    num1 = float(input("Enter first number: "))

    num2 = float(input("Enter second number: "))

except ValueError:

    print("Invalid input! Please enter a valid number.")

• This prevents the program from crashing if the user enters an invalid value (like letters). 

Loop for Continuous Use

Use a while loop to allow the user to perform multiple calculations without restarting the program:

while True:

    # Code for the calculator

    again = input("Do you want to calculate again? (yes/no): ")

    if again.lower() != 'yes':

        break

• This makes the calculator more user-friendly and convenient. 

Output Formatting and Clarity

Explain how f-string improves output clarity and formatting:

print(f"{num1} + {num2} = {num1 + num2:.2f}")

• This ensures that the result is displayed with only two decimal places, making it more professional and easy to read. 

Possible Future Improvements

Suggest some future improvements to make the code more advanced and robust:

•  Support for additional operations (exponentiation, modulus, etc.)

•  Graphical User Interface (GUI) using Tkinter or PyQt

•  Add a calculation history

•  Allow operations with more than two numbers

Comments in Python

In Python, comments are lines of text that are ignored by the interpreter. They are used to explain the code, making it easier for other developers (and your future self) to understand how the code works. Comments are also helpful for debugging and maintaining the code.

Single-Line Comments

To write a single-line comment, use the # symbol at the beginning of the line. Everything after # on that line will be treated as a comment and ignored by the interpreter.

Example:

# This is a single-line comment

x = 5  # You can also add a comment after a statement

• Use single-line comments to explain specific lines of code or to disable code temporarily during testing. 

Multi-Line Comments

Python does not have a dedicated syntax for multi-line comments like /* */ in other languages. However, you can create multi-line comments using triple quotes (''' or """).

Example:

'''

This is a multi-line comment.

You can write as many lines as you want.

Python will ignore all of them.

'''

print("Hello, World!")

• Although this works, triple quotes are technically treated as multi-line strings and not actual comments — but Python will ignore them if they’re not assigned to a variable. 

Why Use Comments?

•  Explain Code Purpose – Help others (and yourself) understand why the code was written a certain way.
   

•  Improve Code Readability – Clean, well-commented code is easier to maintain and debug.
   

•  Temporarily Disable Code – Quickly test different parts of the code by commenting out sections.

Best Practices for Writing Comments

•  Be clear and concise – Write comments that are easy to understand.
   

•  Avoid obvious comments – Don't comment things that are already clear from the code itself.
  
  

•   Use comments to explain "why" – Focus on why the code is written a certain way, not just what it does.

Example:

❌ Bad comment:

x = 10  # Assign 10 to x

• Good comment: 

x = 10  # Initial value for the loop counter

Fun Facts About Python 

• Why the Name "Python"?

Python wasn’t named after the snake! Guido van Rossum, the creator of Python, was a fan of the British comedy series "Monty Python's Flying Circus." He wanted a name that was short, unique, and a little mysterious — so he chose "Python."

• Python's Birthday

Python was created in December 1989 by Guido van Rossum while he was working at the Centrum Wiskunde & Informatica (CWI) in the Netherlands. The first official release, Python 0.9.0, came out in February 1991.

• Python Is Used by Top Companies

Some of the biggest companies in the world, including Google, Netflix, Facebook, Instagram, Spotify, and NASA, use Python for data analysis, machine learning, automation, and web development.

• Python’s Zen

Python has its own set of guiding principles called the Zen of Python. You can view them by running this command in a Python console:

import this

You'll see a poem by Tim Peters that outlines the core philosophy of Python, including ideas like:

"Simple is better than complex."
"Readability counts."

• Python in Games and AI

Python is used to create games and artificial intelligence models. Popular games like Battlefield 2 and Civilization IV use Python for scripting!

• Python is One of the Most Popular Languages

According to the TIOBE Index and Stack Overflow surveys, Python consistently ranks as one of the top programming languages in the world due to its simplicity and versatility.

More Examples Coming Soon!

Thank you for exploring the Python code examples!
We hope these examples have helped you understand the basics of Python programming. We're constantly working to add more content, so stay tuned for new examples and advanced projects coming soon!

If you have any suggestions or specific examples you'd like to see, feel free to share your feedback — we'd love to hear from you!

Happy coding!