Variables & Data Types

03 / 10 Part of python basic

📦 Topic 02 · Data

Variables & Data Types

Learn how Python stores and organises data using variables, and explore the core built-in types you'll use in every program.

⏱ ~35 min
🟢 Beginner
💡 Core concept

What is a Variable?

A variable is a named container that holds a value. In Python you create one simply by assigning to it — no type declaration required. Python figures out the type automatically (this is called dynamic typing).

variables.py

# Assigning variables — no type needed
name       = "Alice"
age        = 30
height     = 1.72
is_student = True

print(name, age, height, is_student)
# Alice 30 1.72 True

📌 Naming Rules

Names must start with a letter or underscore, contain only letters/numbers/underscores, and are case-sensitive. my_var and My_Var are different variables.

Core Data Types

Python has several built-in types. Use type() to inspect any value at runtime.

Type	Example	Description
int	`42`	Whole numbers, positive or negative
float	`3.14`	Numbers with a decimal point
str	`"hello"`	Text — any sequence of characters
bool	`True / False`	Boolean logical values
NoneType	`None`	Represents the absence of a value
list	`[1, 2, 3]`	Ordered, mutable collection
dict	`{"a": 1}`	Key-value pairs

types.py

x    = 10
y    = 3.14
z    = "Python"
flag = False

print(type(x))    # <class 'int'>
print(type(y))    # <class 'float'>
print(type(z))    # <class 'str'>
print(type(flag)) # <class 'bool'>

Type Conversion

Convert between types using built-in functions: int(), float(), str(), bool().

conversion.py

age_str  = "25"
age_int  = int(age_str)    # "25" → 25

price     = 9.99
price_int = int(price)     # 9.99 → 9 (truncates)

count = 42
label = str(count)        # 42 → "42"

print(bool(0))           # False
print(bool(""))          # False
print(bool("hello"))    # True

Multiple Assignment

Python supports concise multiple assignment on one line — handy for unpacking and swapping values without a temp variable.

multi_assign.py

# Assign multiple variables at once
x, y, z = 1, 2, 3

# Swap without a temp variable
x, y = y, x
print(x, y)  # 2 1

# Same value to multiple names
a = b = c = 0

Menu

Variables & Data Types

What is a Variable?

Core Data Types

Type Conversion

Multiple Assignment