Welcome to Python: What It Is and Why It Matters

Python is a general-purpose, high-level programming language created by Guido van Rossum and first released in 1991. It was designed around one core idea: code should be easy to read, even by someone who didn’t write it. That focus on readability is why Python has become one of the most widely used languages in the world, both for beginners writing their first program and for engineering teams running production systems at massive scale.

What makes Python unusual is how far it stretches across different kinds of work. The same language that runs a simple weekend automation script also powers Instagram’s backend, trains machine learning models at companies like OpenAI and Google, drives scientific research through libraries like NumPy and pandas, and automates everyday tasks like renaming files or scraping a website. You will often find one team using Python for a REST API, a data analyst on the same team using it to explore a spreadsheet, and a machine learning engineer using it to train a model — all in the same language, on the same day.

Why Python is a good first language

Python reads close to plain English, which lowers the barrier between the idea in your head and the code on the screen. There’s no need to declare types up front, no semicolons to remember, and no braces to balance — indentation itself defines where a block of code starts and ends, which forces every Python program to at least look organized. A small script can do useful work in just a few lines:

print("Hello, Tutoline!")
name = input("What's your name? ")
print(f"Nice to meet you, {name}")

Compare that to a language like Java or C++, where printing text and reading input typically takes several more lines just to set up. Python trades a little bit of raw execution speed for a large amount of saved development time — and for most applications, that trade is exactly the right one. This is often summarized as Python being ‘batteries included’: the standard library alone covers file handling, networking, dates, math, JSON, and dozens of other everyday needs before you install a single external package.

Installing Python

Download the latest version from python.org for Windows or Linux, or use a package manager on macOS or Linux:

# macOS (with Homebrew)
brew install python

# Ubuntu/Debian Linux
sudo apt update && sudo apt install python3

# Windows
# Download the installer from python.org, or install from the Microsoft Store

On Windows, make sure to check the box labeled “Add Python to PATH” during installation — skipping this is the single most common reason a fresh install doesn’t work from the terminal. Once installed, confirm it worked by opening a terminal (Command Prompt, Terminal, or your code editor’s built-in terminal) and running:

python --version
# or, on some systems:
python3 --version

You should see something like Python 3.12.1 printed back. If you get a “command not found” error, the installation likely didn’t add Python to your system’s PATH — reinstalling with that option checked usually fixes it.

The Python interpreter (REPL)

Before writing a full script, it’s worth getting comfortable with Python’s interactive interpreter, often called the REPL (Read-Eval-Print Loop). Type python in your terminal with no filename, and you’ll get a prompt where you can type Python code one line at a time and see the result immediately:

>>> 2 + 2
4
>>> print("testing")
testing
>>> exit()

This is an excellent way to quickly test a single expression or check how a function behaves, without creating a whole file. Most professional Python developers keep a REPL open constantly, alongside their actual code editor.

Running your first script

Save a file as hello.py using any text editor or IDE (VS Code and PyCharm are both popular, free choices), then run it from the terminal with:

python hello.py

You’ll do this constantly throughout the course — write code in a file, save it, run it from the terminal, read the output, and repeat. It’s worth getting genuinely comfortable with this loop now, since every lesson from here on assumes you can do it without thinking about it.

What you’ll build across this course

By the end of this course you won’t just know Python’s rules — you’ll have written functions, worked with real data structures, built simple classes, read and written files, and called a live web API. Each lesson adds one capability on top of the last, so treat this first one as the foundation everything else stands on.

Tip: use the Forward button below whenever you’re ready — there’s no time limit on any lesson.