Lesson 3 of 12
Variables & Data Types 💾
What You'll Learn
- Create and use variables in Python
- Understand the three main data types: int, float, and str
- Use type() to check a variable's type
What Is a Variable?
A variable is a named container that stores a value. You create one by choosing a name, typing =, and then the value.
Python
name = "Alex" age = 13 height = 5.2 print(name) print(age)
Naming Rules
Variable names: start with a letter or underscore, no spaces (use_underscores_instead), case-sensitive (score and Score are different variables).
The Three Main Data Types
- 🔠 str (string) — text, always in quotes:
"Hello"or'Hello' - 🔢 int (integer) — whole numbers:
42,-7,0 - 🔣 float — decimal numbers:
3.14,99.9
Python
city = "Tulsa" # str population = 413066 # int temp = 98.6 # float print(type(city)) # <class str> print(type(population))
Updating Variables
Variables can change! Just assign a new value with =:
Python
score = 0 print(score) # 0 score = 10 print(score) # 10 score = score + 5 print(score) # 15
Your Profile!
Create variables for: your name (str), your age (int), your grade (int), your GPA or a test score (float). Then print a sentence using each one.
Quick Check
Which data type stores text?
What symbol do you use to create a variable?
What does type(42) return?