Prasath M

 

Data Types in Python

In Python, a data type specifies the kind of value a variable can store and determines the operations that can be performed on it. Python is dynamically typed, meaning you do not explicitly declare the data type—Python infers it at runtime.

Below is a structured explanation of the primary built-in data types.

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1. Numeric Types

1.1 int

Represents whole numbers (positive, negative, or zero).

x = 10
y = -5

• No decimal point

• Unlimited precision (only limited by memory)

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1.2 float

Represents decimal (floating-point) numbers.

pi = 3.14
temp = -2.5

• Uses double precision (64-bit IEEE 754)

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1.3 complex

Represents complex numbers (real + imaginary part).

z = 3 + 4j

• 3 → real part

• 4j → imaginary part

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2. Sequence Types

2.1 str (String)

Represents textual data.

name = "Prasath"
msg = 'Hello'

• Immutable (cannot be changed after creation)

• Supports indexing and slicing

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2.2 list

Ordered, mutable collection of elements.

marks = [80, 75, 90]

• Allows duplicates

• Can store different data types

• Elements can be modified

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2.3 tuple

Ordered, immutable collection.

point = (10, 20)

• Faster than list

• Cannot modify elements after creation

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2.4 range

Represents a sequence of numbers.

r = range(1, 5)

• Used mainly in loops

• Generates numbers from 1 to 4

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3. Set Types

3.1 set

Unordered collection of unique elements.

numbers = {1, 2, 3, 3}

• Automatically removes duplicates

• No indexing

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3.2 frozenset

Immutable version of set.

fs = frozenset([1, 2, 3])

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4. Mapping Type

4.1 dict (Dictionary)

Stores data in key–value pairs.

student = {
    "name": "Prasath",
    "age": 22,
    "dept": "CS"
}

• Keys must be unique

• Mutable

• Very fast lookup (hash table based)

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5. Boolean Type

5.1 bool

Represents logical values.

a = True
b = False

• Used in conditions and comparisons

• Internally subclass of int (True = 1, False = 0)

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6. Binary Types

6.1 bytes

Immutable sequence of bytes.

b = b"hello"

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6.2 bytearray

Mutable version of bytes.

ba = bytearray(5)

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6.3 memoryview

Access memory of binary objects without copying.

mv = memoryview(b"abc")

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7. None Type

7.1 NoneType

Represents absence of value.

x = None

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Checking Data Type

Use the type() function:

x = 10
print(type(x))   # <class 'int'>

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Summary Table

Category	Data Type	Description	Example
Numeric	int	Whole numbers	10, -5
Numeric	float	Decimal numbers	3.14, -2.5
Numeric	complex	Real + imaginary numbers	3 + 4j
Sequence	str	Text data (immutable)	"Hello"
Sequence	list	Ordered, mutable collection	[1, 2, 3]
Sequence	tuple	Ordered, immutable collection	(1, 2, 3)
Sequence	range	Sequence of numbers	range(1, 5)
Set	set	Unordered, unique elements	{1, 2, 3}
Set	frozenset	Immutable set	frozenset([1,2,3])
Mapping	dict	Key–value pairs	{"name":"Prasath"}
Boolean	bool	Logical values	True, False
Binary	bytes	Immutable byte sequence	b"abc"
Binary	bytearray	Mutable byte sequence	bytearray(5)
Binary	memoryview	Memory access object	memoryview(b"abc")
Special	NoneType	No value	None