Python Fundamentals: Getting Started

Welcome to the world of Python! This section is dedicated to the foundational pillars of the language. Before you can build complex applications, you need a solid understanding of the basics: how to set up your environment, how to write code, and the core syntax that makes Python so powerful and readable.

This chapter will guide you through:

Setting Up Your Environment: Choosing the right tools for writing and running Python code.
Basic I/O: Understanding how to get input from a user and display output.
Comments: Learning how to document your code effectively.

Let’s dive in and build a strong foundation for your Python journey.

Setting Up Your Python Environment

To start programming in Python, you need an environment where you can write and execute your code. You have several excellent options, from simple online editors to powerful local setups.

Online Environments (Easiest to Start)

These require no installation and are perfect for beginners.

Google Colab: A free, browser-based environment that’s popular for data science. It’s like a digital notebook where you can write code, see the output, and add notes.
pythonforall.com’s Practice Corner: Our own built-in editor lets you try out code snippets directly on our site.

Local Development (Recommended for Projects)

Installing Python on your computer gives you the most power and flexibility.

Install Python:
- Visit the official Python website.
- Download the latest version for your operating system (Windows, macOS, Linux).
- Crucial Step for Windows: During installation, make sure to check the box that says “Add Python to PATH”. This allows you to run Python from your command line.
Choose a Code Editor:
- VS Code (Visual Studio Code): The most popular choice. It’s a free, powerful, and highly customizable editor. After installing VS Code, get the official Python extension from the marketplace to enable features like debugging, code completion, and linting.
- IDLE: A simple, no-frills editor that comes bundled with the standard Python installation. It’s a good starting point but lacks the features of a modern editor like VS Code.

💡

Our Recommendation: For serious learning and project work, we strongly recommend installing Python and VS Code on your local machine. This setup is the industry standard and will serve you well throughout your programming journey.

Basic Input and Output

A program isn’t very useful if it can’t interact with the user. In Python, this is done through input and output functions.

Output with `print()`

The print() function is used to display information to the user. You can pass it text (strings), numbers, variables, and more.

print("Hello, world!")
print(42)
name = "Alice"
print("Hello,", name)

Input with `input()`

The input() function prompts the user to enter some text and returns their input as a string.

name = input("What is your name? ")
print("Welcome,", name)

⚠️

The input() function always returns a string. If you need to perform mathematical operations, you must convert the input to a number using int() or float().

age_str = input("How old are you? ")
age_int = int(age_str)
print("Next year, you will be", age_int + 1)

The Art of Commenting

Comments are notes in your code that are ignored by the Python interpreter. They are written for humans to read and are essential for explaining why your code does what it does.

Single-Line Comments

Use the hash symbol (#) to start a comment. Everything after the # on that line is ignored.

# This is a single-line comment.
# It's used to explain a specific line of code.
x = 5  # Initialize the starting position.

Multi-Line Comments (Docstrings)

While Python doesn’t have a formal multi-line comment block, triple quotes (""" or ''') are used for this purpose. These are technically strings, but if they are the first statement in a module, function, or class, they become docstrings, which are a special kind of comment used for documentation.

"""
This is a multi-line comment, often used as a docstring.
It can span multiple lines and is great for explaining the
purpose of a function or module.
"""
def add(a, b):
    """This function takes two numbers and returns their sum."""
    return a + b

✅

Good Commenting Practice:

Don’t explain what the code is doing (e.g., # Add 1 to x). The code should be readable enough to show this.
Explain why you are doing it (e.g., # Increment x to account for the boundary condition).
Use comments to leave notes for yourself or other developers.

Introduction Handling Input and Output