# Understanding Classes and Objects in Python

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Now it’s time to clearly understand what a class is and what an object is in Object-Oriented Programming (OOP) using Python.

These two concepts are the **foundation of OOP**, and once you understand them, everything else becomes much easier.

## What Is a Class in Python?

In simple words, a **class is a blueprint or a template for creating objects that share common properties**.

To understand this, let’s use a real-world example.

As discussed in our previous blog, first the **concept of a human being** was created, and then you and I were created from that concept. That **concept** is like a **class**, and our individual existence is like an **object**.

In Python terms:

*   A **class** defines the structure (attributes) and behavior (methods).
    
*   It describes *what an object will look like*
    
*   It doesn’t occupy memory by itself because it’s just a concept.
    

So basically, a **class is just a blueprint**, not a real thing.

## What Is an Object in Python?

An **object** is the actual house built from that blueprint. In programming, we call this an **instance**.

You can think of it this way:

*   **Class = Blueprint**
    
*   **Object = Instance created from that blueprint**
    

In Python, you’ll hear people use **"object"** and **"instance"** interchangeably. Don't let that confuse you they refer to the same thing: the real, usable version of a class.

## Built-in Classes in Python

You might be surprised to learn that you’ve been using classes since Day 1. Every data type in Python—strings, integers, lists, and dictionaries is actually a class.

Try running this in your terminal:

```typescript
            print(type("Hello"))
          //Output: <class 'str'>
```

See that? `str` is a class provided by Python. When you create a string like `name = "Shameel"`, you are actually creating an **object** of the `str` class.

```typescript
            s0 = ""
            s1 = "Shameel"
```

Here:

*   `str` is the **class**
    
*   `str()` creates an **object**
    
*   The parentheses `()` mean that an **object of the class is being created**
    

So:

*   `str` → blueprint
    
*   `str()` → object (instance)
    

This is why we say **class and instance (object) are closely related**

## Literal Syntax in Python

When you write:

```typescript
s2 = "Shameel"
```

This is called **shorthand literal syntax**.

Behind the scenes, Python still creates an **object of the** `str` class. Python just hides this complexity to make the language easy and beginner-friendly.

## Modules and Built-in Classes

Every class in Python belongs to a **module**.

*   The file you run is also considered a **module**
    
*   Built-in classes like `str` belong to the **builtins module**
    

That’s why when you inspect a string class, you’ll see it comes from `builtins`, even though you didn’t import anything manually.

## Objects and Memory in Python

When you create an object, Python carves out a little piece of your computer's RAM to store it. Each object gets a unique "home address."

If you print a custom object, you’ll often see something like this: `<__main__.User object at 0x106558c20>`

That long code at the end (`0x1065...`) is the physical memory address where that specific object lives.

```typescript
<__main__.User object at 0x106558c20>
```

This address shows **where the object exists in memory**.

## Creating a Custom Class in Python

Now let’s move from built-in classes to **custom classes**.

To create your own class in Python, you use the `class` keyword:

```typescript
class User:
    pass
```

Here:

*   `User` is the **class**
    
*   `pass` means the class is empty for now
    

To create an object from this class:

```typescript
u1 = User()
```

The `()` tells Python to **create an object** from the `User` class and store it in the variable `u1`.

You can create multiple objects from the same class:

```typescript
u2 = User()
```

This means:

*   One **class**
    
*   Multiple **objects**
    

Just like one concept of humans, but many human beings.

## **Understanding** `__main__` in Python Output

When you see output like:

```typescript
<__main__.User object>
```

It means:

*   `__main__` is the **current file being executed**
    
*   `User` is the class defined in that file
    

If the class were defined in another file, you would see the module name instead of `__main__`.

## Checking an Object’s Class with `type()`

You can check the class of any object using:

```python
type(u1)
```

Output:

```python
<class '__main__.User'>
```

This confirms that `u1` is an object of the `User` class.

## **Checking Object Instances with** `isinstance()`

This is a great way to "double-check" an object. In programming, any function starting with "is" usually returns a **True** or **False** (Boolean).

Examples:

```python
isinstance(s1, str)   # True
isinstance(s1, int)   # False
isinstance(u1, User)  # True
```

In programming, when a sentence starts with **“Is”**, the result is usually a **Boolean value** (`True` or `False`).

This method is **widely used in Python** to validate object types.

## Summary

*   **Object-Oriented Programming (OOP) in Python** is built around **classes and objects**.
    
*   A **class** is a blueprint that defines structure and behavior.
    
*   An **object (instance)** is a real entity created from a class.
    
*   Python’s built-in data types like **str, int, list, and dict** are actually classes.
    
*   Objects are created using **parentheses** `()` and stored in memory.
    
*   You can create your own **custom classes** using the `class` keyword.
    
*   Use `type()` to check an object’s class.
    
*   Use `isinstance()` to verify whether an object belongs to a specific class.
    
*   Understanding classes and objects is essential for mastering **Python OOP**.
    

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