Home / Python / Day 1: Python Basics / Variables

Variables

Variables store data values. Python uses dynamic typing — no need to declare types.

Variables in Python

A variable is a named container that stores a value. Python is dynamically typed, meaning you do not declare the type — Python infers it automatically.

Variable Naming Rules

Must start with a letter or underscore
Can contain letters, numbers, underscores
Cannot be a Python keyword
Case-sensitive

Multiple Assignment

Python allows multiple assignment in one line.

Type Checking

Use type() to check the data type of a variable.

Syntax

<pre><code># Variable assignment
name = "Alice"
age = 25
price = 9.99
is_active = True

# Multiple assignment
x = y = z = 0

# Tuple unpacking
a, b, c = 1, 2, 3

# Swap variables (Pythonic!)
a, b = b, a

# Type checking
print(type(name))    # <class "str">
print(type(age))     # <class "int">
print(type(price))   # <class "float">
print(type(is_active))  # <class "bool">

# Delete a variable
del name
</code></pre>

Revision Notes

• Dynamic typing — no type declaration needed
• Use snake_case for variable names
• type() returns the data type
• del removes a variable
• Multiple assignment: a, b = 1, 2

Example 1: Variable Examples

name = "Alice"
age = 25
height = 5.7
is_student = True

print(name)       # Alice
print(age)        # 25
print(height)     # 5.7
print(is_student) # True

Demonstrates all four basic variable types.

Example 2: Multiple Assignment

# Assign same value to multiple variables
x = y = z = 0
print(x, y, z)  # 0 0 0

# Unpack multiple values at once
a, b, c = 10, 20, 30
print(a, b, c)  # 10 20 30

# Swap without temp variable
a, b = b, a
print(a, b)  # 20 10

Python allows elegant multiple assignment and swapping.

Greet the User

Easy

Write a Python program that asks for a user's name and age, then prints a personalized greeting message.

The program should:
1. Ask for the user's name
2. Ask for their age
3. Print: "Hello, [Name]! You are [age] years old. In 10 years, you will be [age+10]."

Input:

Alice 25

Output:

Hello, Alice! You are 25 years old. In 10 years, you will be 35.

Show Hint

Use input() to get user data. Convert age to int() for arithmetic.

Solve this Challenge

Show Solution

name = input("Enter your name: ")
age = int(input("Enter your age: "))
print(f"Hello, {name}! You are {age} years old. In 10 years, you will be {age + 10}.")

Python Syntax Data Types