Python provides many built-in classes that make programming simple and powerful. You can use these classes directly without defining them yourself.

If you are coming from C, C++, or Java, you may already know concepts such as int, float, char, arrays, and classes. Python uses some similar concepts, but its object model is different.

In Python, commonly used data types such as integers, floating-point numbers, strings, lists, and dictionaries are represented by built-in classes.

What Is a Built-in Class in Python?

A built-in class is a class that Python provides for us.

We do not have to define these classes before using them.

For example:

x = 10

Here:

• int is a built-in Python class.
• 10 is an object (instance) of the int class.
• x is a name that refers to that object.

We can check the type of x using:

print(type(x))

Output:

<class 'int'>

So, in simple terms:

int → built-in class
10 → object of the int class
x → name referring to the object

Built-in Classes vs Data Types

In languages such as C, you may write:

int x = 10;

Here, int is a built-in data type and x is an integer variable.

In Python, we write:

x = 10

Python does not require us to declare the type of x separately.

The object 10 has type int, and the name x refers to that object.

This is one of the important differences between Python and languages such as C, C++, and Java.

Common Built-in Classes in Python

Python has many built-in classes. As a beginner, you will frequently work with the following ones:

Built-in class	Used for	Example
int	Integers	10
float	Decimal numbers	3.14
complex	Complex numbers	2+3j
bool	True/False values	True
str	Text	“Python”
list	Ordered, changeable collection	[10, 20, 30]
tuple	Ordered, unchangeable collection	(10, 20, 30)
set	Unique elements	{10, 20, 30}
dict	Key-value pairs	{“name”: “Ram”}
range	Sequence of integers	range(5)

A Simple Comparison with C, C++ and Java

If you have learned C, C++, or Java, the following comparison can help.

C

You might write:

int x = 10;
float price = 3.14;

Here, int and float are built-in data types.

Python

You write:

x = 10
price = 3.14

Python automatically associates the objects with their types.

10       → int object
3.14     → float object
"Hello"  → str object
[1, 2]   → list object

In Python, you don’t normally declare a variable’s type before assigning a value.

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Python’s Object-Oriented Approach

This is one of the interesting features of Python.

Consider:

x = 10

The number 10 is an object of the int class.

Similarly:

name = "Python"

"Python" is an object of the str class.

And:

numbers = [10, 20, 30]

The list is an object of the list class.

So we can think of Python like this:

Built-in Class       Example Object

int       ─────────→  10
float     ─────────→  3.14
str       ─────────→  "Python"
list      ─────────→  [10, 20, 30]
tuple     ─────────→  (10, 20, 30)
set       ─────────→  {10, 20, 30}
dict      ─────────→  {"name": "Ram"}

This object-based approach is one reason Python is easy to extend with your own classes.

Quick Revision

Remember these important points:

• Python provides many built-in classes.
• int represents integer numbers.
• float represents decimal numbers.
• complex represents complex numbers.
• bool represents True and False.
• str represents text.
• list represents an ordered, changeable collection.
• tuple represents an ordered, unchangeable collection.
• set represents a collection of unique elements.
• dict represents key-value pairs.
• range represents a sequence of integers.
• Values created from these classes are objects.
• Python does not normally require you to declare a variable’s type before assigning a value.

Final Thought

If you are coming from C, C++, or Java, it may take a little time to become comfortable with Python’s object model.

A simple way to remember it is:

In Python, classes define objects, and names are used to refer to those objects.

Once you understand this idea, many other Python concepts—including lists, strings, functions, classes, and object-oriented programming—become much easier to understand.