# Abstraction

* Abstraction allows you to create abstract classes and methods to represent common characteristics and behaviors of a group of related objects.
    
* It focuses on hiding the internal implementation details of a class and providing a simplified interface for interacting with objects.
    
* In Python, abstraction is achieved through abstract classes and methods using the `abc` module, which stands for "Abstract Base Classes".
    

### Abstract Classes

* An abstract class is a class that cannot be instantiated and acts as a **blueprint** for creating subclasses.
    
* It is a common interface or application programming interface(API) for concrete subclass.
    

```python
from abc import ABC, abstractmethod

#Abstract class
class Shape(ABC):
    @abstractmethod
    def area(self):
        pass

obj = Shape()
obj.area()
```

**Output**

```python
TypeError: Can't instantiate abstract class pen with abstract method area
```

In this example, `Shape` is an abstract class that defines an abstract method`area()`. The `abstractmethod` decorator indicates that these methods must be implemented in the child subclasses derived from the `Shape` class. Attempting to create an instance of the `Shape` class directly will result in a `TypeError`.

```python
from abc import ABC, abstractmethod

#Abstract class
class Shape(ABC):
    @abstractmethod
    def area(self):
        pass

class Circle(Shape):
    pass

obj = Circle()
```

**Output**

```python
TypeError: Can't instantiate abstract class pen with abstract method area
```

If I implement the **radius()** method in the child class then it executes with error-free

```python

from abc import ABC, abstractmethod

#Abstract class
class Shape(ABC):
    @abstractmethod
    def area(self):
        pass

'''
Circle class inherit abstract class Shape ,so it is mandatory to use 
method of parent/abstract class in this child class
'''
class Circle(Shape):
    def __init__(self, radius):
        self.radius = radius
    
    def area(self):
        return 3.14 * self.radius**2


obj = Circle(2)
area = obj.area()
print(f"Area is : {area}")
```

**Output :**

```python
Area is : 12.56
```

In this example, the `Circle` class is a subclass of the `Shape` abstract class. It provides implementations for the `area()` and `perimeter()` methods, which are required by the `Shape` abstract class. The `Circle` class can be instantiated, and its methods can be called to perform specific calculations related to circles.