Python Tutorials

Choose a lesson to begin

Hello World and Print Statements
Learn the basics of printing output in Python
Beginner
Variables and Data Types
Store and work with different types of data
Beginner
Math and Arithmetic
Perform calculations and mathematical operations
Beginner
F-Strings and Formatting
Format text output with embedded variables
Beginner
String Methods
Transform and manipulate text with built-in methods
Beginner
Lists and For Loops
Store multiple items and iterate through them
Beginner
List Comprehensions and Generator Expressions
Master concise, Pythonic ways to create and transform sequences
Intermediate
Dictionaries and Advanced Data Structures
Master key-value mappings, nested structures, and efficient data organization
Intermediate
Functions, Decorators, and Functional Programming
Write reusable code with functions, decorators, lambda expressions, and functional patterns
Intermediate
Object-Oriented Programming (OOP)
Master classes, objects, inheritance, and OOP design patterns
Advanced
Error Handling and Exceptions
Handle errors gracefully with try-except, custom exceptions, and error recovery
Intermediate
File I/O and Data Persistence
Read and write files, work with JSON/CSV, and persist application data
Advanced

Variables and Data Types

Variables are like labeled boxes that store information. Once you put data in a variable, you can use it over and over again.

Creating Variables

To create a variable, use the = sign (assignment operator):

name = "Vidar"
age = 22

Now name holds the text "Vidar" and age holds the number 22.

Data Types

Python has several basic data types:

Strings (Text)

Strings are text, wrapped in quotes:

greeting = "Hello!"
city = 'Roskilde'  # single or double quotes work

Numbers

Integers are whole numbers: 

score = 100
year = 2024

Floats are decimal numbers: 

price = 19.99
temperature = -5.5

Booleans (True/False)

Booleans represent yes/no, true/false:

is_raining = True
is_sunny = False

Note: True and False are capitalized!

Using Variables

Once created, use variables by their name:

name = "Bob"
age = 30
print(name, "is", age, "years old")

Output: Bob is 30 years old

Variables Can Change

You can update a variable's value:

score = 0
print(score)  # 0
score = 10
print(score)  # 10
score = score + 5
print(score)  # 15

Naming Rules

Good names: Bad names:

Try It Out!

  • Create variables for your name, age, and favorite color
  • Print them in a sentence
  • Change one variable and print again
  • Store two numbers in variables and print their sum

    • Next Steps

    Ready to do math with Python? Check out Math and Arithmetic next!

    🐍 Python Runner