00: Pregătire

Install Thonny, understand what Python is, and write your first program.

python installation thonny first-program

Lesson 00 · Getting started

What you'll learn

  • What Python is and what it's used for
  • How to install and use the Thonny IDE
  • How to write and run your first Python program
  • How to read an error message

What is Python?

Python logo

Python is a programming language created in 1991 by Guido van Rossum. Today it is one of the most popular languages in the world — and for good reasons:

  • It reads almost like plain English
  • It works on Windows, macOS, and Linux
  • It is used for games, artificial intelligence, websites, data analysis, robotics

Python is free

Python is open-source. You can download, use, and distribute it without any restrictions.

Our tool: Thonny

Thonny is a code editor created specifically for learning Python. It is simple, has a visual debugger, and comes with Python already included.

Installation

  1. Go to https://thonny.org
  2. Download the version for your system (Windows / macOS / Linux)
  3. Run the installer — all default settings are fine
  4. Open Thonny

Online alternative

If you can't install programs, use repl.it — create a free account and run Python directly in the browser.

What Thonny looks like

Thonny IDE interface

The interface is split into two main areas:

  • The Editor (top) — where you write programs
  • The Shell (bottom) — where results appear when you run code

Your first program

1. Write the code

In the Thonny editor, type exactly:

print("Hello, world!")

2. Run

Press the ▶ Run button or the F5 key.

3. Look at the result

Hello, world!

Congratulations — you've written your first Python program!

The print() function

print() is a function — a ready-made block of code that does something. In this case, it displays text on the screen.

The text goes between quotes (single ' or double ") and inside parentheses:

print("Python is fun!")
print('And I can program too.')
print("Ursoaia Edu Online")

Each print() displays a new line.

Reading errors

Mistakes are normal and inevitable. Here's an example:

print("Hello, world!"

Python will display:

SyntaxError: '(' was never closed

Translation: the ( parenthesis was never closed.

Fix: add ) at the end.

Errors are your friends

Every error tells you exactly what went wrong and on which line. Read the message carefully before changing the code.

The interactive shell

In the bottom area of Thonny you can test Python commands directly, without saving a file:

>>> 2 + 3
5
>>> "Anna" + " has " + "apples"
'Anna has apples'

>>> means Python is waiting for a command. Ideal for quickly testing ideas.

Exercises

Exercise 1 — Three things about you

Write a program that displays your name, age, and home town, each on a separate line.

Solution 
print("Mary")
print(14)
print("Timișoara")

Exercise 2 — How many lines?

How many lines will the following program display?

print("One")
print("Two")
print("Three")
Answer

3 lines. Each print() produces a new line.

Exercise 3 — Find the error

What's wrong?

print("Good day!
Answer

The closing quote " and closing parenthesis ) are missing. 

print("Good day!")

Mini-project: Your business card

Write a program that displays a business card with information about you.

Example output: 

==============================
  My name: Mary Ionescu
  Age: 14 years
  School: Theoretical High School X
  Hobbies: programming, soccer
==============================

Solution 

print("==============================")
print("  My name: Mary Ionescu")
print("  Age: 14 years")
print("  School: Theoretical High School X")
print("  Hobbies: programming, soccer")
print("==============================")
Edit it with your real information!

Summary

  • Python is a simple and powerful programming language
  • Thonny is our recommended editor for writing code
  • print() displays text on the screen
  • Errors are normal — read the message and fix it

Next step: → Lesson 01: Variables and data types

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