Python Basics

Variables & Data Types

Foundation concepts of Python programming — learn how to store and work with data effectively.

Python 3 ✓ Beginner Friendly 2 Topics

Variables in Python

A variable is a name used to store data in memory. Python is dynamically typed and case-sensitive: age, Age, and AGE are three different variables.

Python — Variables

# Creating variables — just assign a value
x = 10
name = "Alice"
is_student = True

# Case sensitivity demo
age = 20
Age = 30
print(age)   # 20
print(Age)   # 30

# Updating a variable
count = 1
count = 2   # value updated

Naming Rules

✓ Valid Names

total_marks
student_name
_count
value2

✗ Invalid Names

2marks — starts with number
total-marks — contains hyphen
for — Python keyword

Data Types in Python

Type	Keyword	Example	Used For
Integer	`int`	`age = 25`	Counting, indexing, loops
Float	`float`	`pi = 3.14`	Measurements, prices
String	`str`	`name = "Alice"`	Text, names, messages
Boolean	`bool`	`flag = True`	Conditions, loops
None	`NoneType`	`result = None`	No value / empty state
Complex	`complex`	`z = 3 + 4j`	Scientific calculations

Type Conversion Rules: Allowed: int→float, int→complex, float→complex, int→str. NOT allowed: complex→int or complex→float directly (use int(z.real) instead).

✓

Quick Quiz

1. Which of these is mutable in Python?

2. What does type(3.14) return?

3. Which value is falsy?

4. Valid f-string syntax?

5. What is None's type?

← Previous Collections →