Variables and Assignment — Python Basics

What You Will Learn

A variable is a name that stores a value. Instead of writing the same value over and over, you store it once and use the name everywhere.

Creating a Variable

Use = to assign a value to a variable:

name = "Alice"
age = 25
height = 1.68

Now you can use those names anywhere in your program:

name = "Alice"
age = 25

print(name)
print(age)

Expected output:

Alice
25

Using Variables in print()

You can print multiple things on one line by separating them with commas:

name = "Alice"
age = 25

print("My name is", name)
print("I am", age, "years old")

Expected output:

My name is Alice
I am 25 years old

Python automatically adds a space between items separated by commas.

Changing a Variable

Variables can change. That is why they are called variables:

score = 0
print(score)

score = 10
print(score)

score = score + 5
print(score)

Expected output:

0
10
15

score = score + 5 means: take the current value of score, add 5, and store the result back into score.

Variable Naming Rules

Variable names can contain letters, numbers, and underscores. They cannot start with a number.

# Valid names
first_name = "Alice"
age2 = 25
total_score = 100

# Invalid names (these will cause errors)
# 2fast = True       ← cannot start with a number
# my-name = "Alice"  ← hyphens are not allowed
# my name = "Alice"  ← spaces are not allowed

Python variable names are case-sensitive. name, Name, and NAME are three different variables.

Descriptive Names

Always choose names that describe what the variable stores:

# Hard to understand
x = 25
y = "Alice"
z = 1000

# Easy to understand
age = 25
name = "Alice"
monthly_salary = 1000

Good variable names make your code readable without needing extra comments.

What You Learned

Variables store values under a name
Use = to assign a value
Variables can be reassigned at any time
Names must follow Python’s naming rules
Descriptive names make code easier to read

In the next lesson, you will learn about the different data types Python uses to represent numbers, text, and other kinds of information.