Python Data Types

What Are Data Types in Python?

In programming, a data type defines what kind of value a variable can hold and how that value can be used. Python automatically determines a variable’s type at runtime, so explicit type declarations are not required. This flexibility makes Python a dynamically typed language.

You can check the type of any value or variable using the built-in type() function.

Built-In Data Types in Python

Python includes several built-in data types. These are categories of objects the language supports natively:

Numeric Data Types

Numeric types represent numbers:

• int: Whole numbers (e.g. 10, -5).

• float: Decimal numbers (e.g. 3.14, 2.0).

• complex: Numbers with real and imaginary parts (e.g. 2 + 3j).

Example:

x = 10

Text Type

• str: Used for text, created with single ('...') or double ("...") quotes.

Example:

name = "Python" print(type(name)) # <class 'str'> 

Strings can also be multi-line using triple quotes ("""...""").

Sequence Types

Sequence types allow storing ordered collections:

• list: Mutable sequence (e.g. [1, 2, 3]).

• tuple: Immutable sequence (e.g. (1, 2, 3)).

• range: Represents a sequence of numbers (e.g. range(5)).

Example:

fruits = ["apple", "banana", "cherry"] print(type(fruits)) # <class 'list'> 

Mapping Type

• dict: Stores key-value pairs (e.g. {"name": "Alice", "age": 30}).

Example:

person = {"name": "Alice", "age": 30} print(type(person)) # <class 'dict'> 

Dictionaries are unordered (prior to Python 3.7) and allow fast lookup by key.

Set Types

• set: Unordered collection of unique elements.

• frozenset: Immutable version of a set.

Example:

numbers = {1, 2, 3, 3} print(numbers) # {1, 2, 3} print(type(numbers)) # <class 'set'>

Sets automatically remove duplicates.

Boolean Type

• bool: Holds one of two values: True or False. Often used in conditions and loops.

Example:

a = True print(type(a)) # <class 'bool'> 

Booleans are also subclasses of integers (True == 1, False == 0).

Binary Types

Binary types represent raw bytes of data:

• bytes: Immutable sequence of bytes.

• bytearray: Mutable sequence of bytes.

• memoryview: View of another binary object without copying.

Example:

data = b"Hello" print(type(data)) # <class 'bytes'>

None Type

• NoneType: Represents the absence of a value. There is only one None object in Python.

Example:

result = None print(type(result)) # <class 'NoneType'>

This type often acts as a placeholder.

Checking and Converting Types

Use type() to check a data type. You can convert between types using functions like int(), float(), str(), etc.

Example:

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