class A:
	def __init__(self,name,age):
		self.name = "shun"
		self.age = 18
	def eat(self):
		print (" i want to eat")
A.eat()

　　報錯， self 表示例項， A.eat()沒有傳入例項

class A:
    def __init__(self,name,age):
        self.name = "shun"
        self.age = 18
    def eat(self):
        print (" i want to eat
 
")

a = A("shun",'12')
a.eat()

#把 例項a 作為self引數傳給A object
A.eat(a)

class A:
    def __init__(self,name,age):
        self.name = "shun"
        self.age = 18
    def eat(self):
        print (self," i want to eat")

a = A("shun",'12')
a.eat()

#把 例項a 作為self引數傳給A object
A.eat(a)


#使用類來呼叫類的方法， self引數必須要傳入， 但是並不一定要求傳入類A的例項，下面的方式也可以呼叫
 

A.eat("a person say")

<__main__.A object at 0x000001CFC670A430>  i want to eat
<__main__.A object at 0x000001CFC670A430>  i want to eat
a person say  i want to eat