Penggantian Method dan super()

Pendahuluan

Dasar-Dasar Penimpaan

class Greeter:
    def greet(self): return 'Hello'
class FormalGreeter(Greeter):
    def greet(self): return 'Good day'
print(FormalGreeter().greet())

super() dalam Penimpaan

class Logger:
    def log(self, msg): print(f'[LOG] {msg}')
class TimedLogger(Logger):
    def log(self, msg):
        import time
        super().log(f'{time.time():.0f}: {msg}')
TimedLogger().log('test')

super() dalam __init__

class Animal:
    def __init__(self, name): self.name = name
class Cat(Animal):
    def __init__(self, name, indoor):
        super().__init__(name)
        self.indoor = indoor
cat = Cat('Whiskers', True)
print(cat.name, cat.indoor)

super() dengan Argumen

class A:
    def greet(self): return 'A'
class B(A):
    def greet(self): return super().greet() + 'B'
class C(B):
    def greet(self): return super().greet() + 'C'
print(C().greet())

Pewarisan Kooperatif

class A:
    def __init__(self): print('A init')
class B(A):
    def __init__(self): super().__init__(); print('B init')
class C(A):
    def __init__(self): super().__init__(); print('C init')
class D(B, C):
    def __init__(self): super().__init__(); print('D init')
D()

Menimpa __str__

class Animal:
    def __init__(self, name): self.name = name
    def __str__(self): return f'Animal: {self.name}'
class Dog(Animal):
    def __str__(self): return f'Dog: {self.name}'
print(Dog('Rex'))

Pola Metode Templat

class DataProcessor:
    def process(self):
        data = self.load()
        return self.transform(data)
    def load(self): return [1,2,3]
    def transform(self, d): return d
class Doubler(DataProcessor):
    def transform(self, d): return [x*2 for x in d]
print(Doubler().process())

Memanggil Metode Saudara

class A:
    def hello(self): print('A')
class B(A):
    def hello(self): super().hello(); print('B')
class C(A):
    def hello(self): super().hello(); print('C')
class D(B,C):
    def hello(self): super().hello(); print('D')
D().hello()

__init_subclass__

class Plugin:
    registry = []
    def __init_subclass__(cls, **kw):
        super().__init_subclass__(**kw)
        Plugin.registry.append(cls)
class A(Plugin): pass
class B(Plugin): pass
print([c.__name__ for c in Plugin.registry])

Kapan TIDAK Menimpa

# Good: only override what's needed
class Dog(Animal):
    def speak(self): return 'Woof'
    # No need to override __init__ if parent's is fine
print('override guidance')

Pemeriksaan Singkat

Ringkasan

Lanjutkan