Chapter-2-Data-Types & Variables

Variables and Data Types

Variables are containers for storing data values. Python has no command for declaring a variable; it is created the moment you first assign a value to it.

x = 5
y = "John"
print(x)
print(y)

Built-in Data Types

In programming, data type is an important concept. Variables can store data of different types, and different types can do different things. Python has the following data types built-in by default:

Category	Data Type	Example Syntax
Text Type	str	"Hello, World!"
Numeric Types	int, float, complex	10, 3.14, 2 + 3j
Sequence Types	list, tuple, range	[1, 2, 3], (1, 2), range(5)
Mapping Type	dict	{"name": "Alice", "age": 25}
Set Types	set, frozenset	{1, 2, 3}, frozenset({1, 2, 3})
Boolean Type	bool	True, False

Examples of Data Types

# String
greeting = "Hello World"

# Integer
age = 20

# Float
price = 19.99

# List (ordered and changeable)
fruits = ["apple", "banana", "cherry"]

# Tuple (ordered and unchangeable)
coordinates = (10, 20)

# Dictionary (key-value pairs)
person = {"name": "John", "age": 36}

# Boolean
is_active = True

and you can declare a variable simply by initializing it ,

x = int()

you can directly start a new variable with a data instead of even telling the data type eg. x=5 is perfectly valid if x isn't even declared. (not exactly recommended for a project level development)