Your First Python Program

One line, and it works. That's the whole setup.

In Setting Up, you installed Python and a code editor. Now let's write a program from scratch and understand every character in it.

Here's the most famous first program in any language, written in Python:

print("Hello, world!")

Hello, world!

That's it. No setup lines, no wrapper around it. If you took the Java track, you'll remember that Java needed a class and a main method just to print one line. Python lets you get straight to the point.

Asking Python to say something

Think of print as a messenger standing by the door. You hand the messenger a note, and they read it out loud, then step back and wait for the next note.

print("Hello, world!")

• print is the messenger's name. It's a function: a named action Python already knows how to do.
• The parentheses ( ) are how you hand something to a function. Whatever goes inside is what you're giving it.
• "Hello, world!" is the note. Text in quotes is called a string.

Every call to print prints its text, then moves down to a new line. So a program with three print lines prints three lines, in order, from top to bottom:

print("Line one")
print("Line two")
print("Line three")

Line one
Line two
Line three

Single or double quotes

Python accepts strings in either kind of quotes, as long as the start and end match:

print("Hello")
print('Hello')

Hello
Hello

Both do exactly the same thing. That choice comes in handy when your text contains a quote mark itself:

print("It's a sunny day.")
print('She said "hi" to me.')

It's a sunny day.
She said "hi" to me.

The apostrophe in It's is fine inside double quotes, and the double quotes around "hi" are fine inside single quotes. Pick one style for most of your code (this track uses double quotes), and switch only when the text needs it.

Special characters: the backslash

What if a string needs both kinds of quotes, or a line break in the middle? Put a backslash \ in front of a special character:

print("She said \"hi\" and left.")
print("First line\nSecond line")

She said "hi" and left.
First line
Second line

\" means "a real quote mark, not the end of the string." \n means "start a new line here." These pairs are called escape sequences.

Printing several things at once

You can hand print several things, separated by commas. It prints them all on one line with a space between each:

print("Maria", "is", 17)

Maria is 17

Notice that 17 has no quotes. It's a number, not text, and print handles both. You'll learn all about numbers in Numbers, Strings, and Booleans.

print also has two optional settings. sep changes what goes between the items, and end changes what goes at the end instead of a new line:

print("2026", "09", "29", sep="-")
print("Loading", end="...")
print("done!")

2026-09-29
Loading...done!

Because the second print ended with ... instead of a new line, the third one continued on the same line.

Comments

A # starts a comment. Python ignores everything from the # to the end of the line:

# This program greets the class.
print("Good morning, class!")  # printed first

Good morning, class!

Use comments to explain why your code does something, not to repeat what it obviously does. # greet the class above a greeting doesn't help anyone. # the principal asked for a morning greeting on every report might.

The mistakes everyone makes

Python is friendly, but it's also exact. Here are the errors almost every beginner hits in their first week, and what they mean.

A missing closing quote.

print("Hello, world!)  # error: SyntaxError: unterminated string literal

Python reached the end of the line while still inside a string. Add the missing ".

A missing closing parenthesis.

print("Hello, world!"  # error: SyntaxError: '(' was never closed

Every ( needs a matching ).

A capital P.

Print("Hello, world!")  # error: NameError: name 'Print' is not defined

Python is case-sensitive. print is a function; Print is just a name nobody created. Python even suggests the fix: Did you mean: 'print'?

A space at the start of the line.

 print("Hello, world!")  # error: IndentationError: unexpected indent

In Python, spaces at the start of a line mean something: they show which lines belong together. You'll use that on purpose in Making Decisions. A line that's indented for no reason is an error.

When you see an error, read it from the bottom. The last line says what kind of problem it is, and the lines just above it show the line number and a little ^ or ~ pointing at the exact spot.

Try it

This program prints a small student ID card. Predict exactly what it prints, including where each line breaks, before you check.

Running Python here

Running Python right in the browser is coming to Syntaxia soon. For now, you can read and edit the code here. If you have Python installed on your computer (see Setting Up), save it as main.py and run it with python main.py (or python3 main.py on macOS and Linux).

Check your prediction

=== STUDENT ID ===
Name: Maria Santos
Grade: 11
Motto: "Measure twice, cut once."
Clubs: Chess & Robotics
==================

sep=" " on the Grade line changes nothing, because a space is already the default. The Clubs line ends with a space instead of a new line, so the next print continues right after it, joining its two items with " & ".

Try it yourself

1. Change the name and grade to your own, and add a line that prints your favorite subject.
2. Print today's date with the parts separated by slashes, like 29/09/2026, using a single print call with three items and sep.
3. Delete the closing quote on any line and run the program on your computer. Read the error from the bottom up: which line does it point to? Then put the quote back.

Check your understanding

What does print("A", "B", "C") print?

ABC

A B C

A, B, C

An error

Which line prints the text It's done. correctly?

print('It's done.')

print(It's done.)

print("It's done.")

Print("It's done.")

Python shows an error. Where should you start reading it?

The last line, which names the kind of problem

The first line only

Nowhere, just try again

The middle

Up next

You've run a Python program. But what actually happens between typing the code and seeing the output, and what's that >>> prompt people talk about? That's How Python Runs.