Python somo la 30: Data abstraction

Data Abstraction in Python

Data Abstraction ni mchakato wa kuficha maelezo ya utekelezaji wa data huku ukitoa interface rahisi kwa mtumiaji. Hii inaruhusu kuangazia kile ambacho object inafanya badala ya jinsi inavyofanya kazi.

Jinsi Data Abstraction Inavyofanya Kazi:

• Abstraction inalenga kuhifadhi maelezo ya ndani ya code yasionekane moja kwa moja kwa mtumiaji.

• Hii hufanikishwa kwa kutumia abstract classes na methods ambazo hazina utekelezaji kamili katika class ya msingi (base class).

Vipengele Muhimu vya Data Abstraction:

1. Abstract Class:

• Hii ni class inayojumuisha angalau abstract method moja.

• Abstract class haiwezi kuanzishwa moja kwa moja, yaani huwezi kuunda object ya abstract class.

2. Abstract Method:

• Hii ni method isiyo na utekelezaji katika class ya msingi.

• Inapaswa kufafanuliwa kwenye class zinazorithi (subclasses).

3. Module abc:

• Python hutumia module ya abc (Abstract Base Classes) kuunda classes za abstract na methods zake.

Hatua za Kutengeneza Abstract Class na Abstract Methods

Kabla ya kuziona hatuwa hizo kwanz anakuletea mfano ambao tutakwenda kuufanyia kazi

from abc import ABC, abstractmethod

# Abstract Class

class Shape(ABC):

    @abstractmethod

    def area(self):

        pass

    @abstractmethod

    def perimeter(self):

        pass

# Concrete Class

class Rectangle(Shape):

    def __init__(self, length, width):

        self.length = length

        self.width = width

    def area(self):

        return self.length * self.width

    def perimeter(self):

        return 2 * (self.length + self.width)

# Object creation

rect = Rectangle(5, 3)

print(f"Area: {rect.area()}")        # Output: Area: 15

print(f"Perimeter: {rect.perimeter()}")  # Output: Perimeter: 16

Hatua ya 1: Ku-import ABC na abstractmethod

Python hutumia moduli ya abc:
from abc import ABC, abstractmethod

• ABC inatumika kama mzazi wa abstract class.

• @abstractmethod ni decorator inayotangaza method kuwa abstract.

Hatua ya 2: Kutengeneza Abstract Class

• Unda class inayorithi kutoka ABC.

• Tangaza methods zote unazotaka kuwa abstract kwa kutumia @abstractmethod.

Mfano:
class Shape(ABC):

    @abstractmethod

    def area(self):

        pass

    @abstractmethod

    def perimeter(self):

        pass

Katika code hizo tunapata kuwa:

1. Shape ni abstract class.

2. area na perimeter ni abstract methods (hazina utekelezaji).

Hatua ya 3: Kutengeneza Child Class na Kutekeleza Abstract Methods

• Unda child class inayorithi kutoka kwa abstract class.

• Lazima child class itekeleze abstract methods zote za mzazi wake.

Mfano:
class Rectangle(Shape):

    def __init__(self, length, width):

        self.length = length

        self.width = width

    def area(self):

        return self.length * self.width

    def perimeter(self):

        return 2 * (self.length + self.width)

Katika code hizo tunapata kuwa:

1. Rectangle inatekeleza abstract methods area na perimeter.

2. Pia, inachukua constructor (__init__) ili kuweka thamani za length na width.

Hatua ya 4: Kutengeneza Object Kutoka kwa Child Class

• Abstract class haiwezi kutengeneza object moja kwa moja. Object hutengenezwa kwa child class ambayo imetekeleza abstract methods.

Mfano:
rect = Rectangle(5, 3)

print(f"Area: {rect.area()}")        # Output: Area: 15

print(f"Perimeter: {rect.perimeter()}")  # Output: Perimeter: 16

Ufafanuzi wa Msimbo

1. Shape:

• Ni abstract class inayotangaza area na perimeter kama abstract methods.

• Inatoa kiolezo (template) kwa child classes.

2. Rectangle: