Python object-oriented (2)-inheritance (1)

Single inheritance

#所有类默认继承object
class Gun(object):
	def __init__(self,width):
		self.length = 100
		self.width = width
	def shoot(self):
		print('bang')
		
class Wuzi(Gun):
	pass

wuzi = Wuzi(3)

wuzi.shoot()
		

As shown in the above example, Gun is called the parent class, Wuzi is the subclass, Wuzi inherits Gun, and automatically inherits the properties and methods of the parent class. At this time, only one parent class is written in the brackets after Wuzi, which is called single inheritance.

Multiple inheritance

class Gun1(object):
	def __init__(self):
		self.length = 100
		
	def shoot(self):
		print('bang1')
		
class Gun2(object):
	def __init__(self):
		self.length = 200
		
	def shoot(self):
		print('bang2')
		
class Wuzi(Gun1,Gun2):
	pass

wuzi = Wuzi()

wuzi.shoot()

At this time, the output is bang1, that is:
when a class inherits multiple parent classes, the same-named methods and properties of the first parent class are used by default

Subclass overrides the properties and methods of the parent class with the same name

class Gun1(object):
	def __init__(self):
		self.length = 100
		
	def shoot(self):
		print('bang1')
		
class Gun2(object):
	def __init__(self):
		self.length = 200
		
	def shoot(self):
		print('bang2')
		
class Wuzi(Gun1,Gun2):
	def shoot(self):
		print('bang3')

wuzi = Wuzi()

wuzi.shoot()

The output at this time is bang3