Variables in Python

What is a Variable?

• A variable is like a container that stores data in your program.
• It allows you to name a value so you can use it later.
• Think of it as a label you stick on a box to remember what’s inside.

Creating a Variable

In Python, you don’t need to declare the type of a variable. Just assign a value using the = sign:

name = "Alice"
age = 25
height = 5.7

• name stores a string ("Alice")
• age stores an integer (25)
• height stores a floating‑point number (5.7)

Rules for Naming Variables

• Must start with a letter or underscore (_)
• Cannot start with a number
• Can only contain letters, numbers, and underscores
• Case‑sensitive (Name and name are different)
• Use descriptive names for clarity (e.g., student_name instead of sn)

Using Variables

Once a variable is created, you can use it in your program:

name = "Alice"
age = 25

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

Output:

My name is Alice
I am 25 years old

Updating Variables

You can change the value stored in a variable:

age = 25
age = age + 1
print("Next year I will be", age)

Output:

Next year I will be 26

Multiple Assignments

Python allows assigning values to multiple variables in one line:

x, y, z = 10, 20, 30
print(x, y, z)

Output:

10 20 30