python对象销毁(垃圾回收)

'''python对象销毁(垃圾回收)'''

class Point:
    'info class'
    def __init__(self,x=0,y=0):
        self.x = x
        self.y = y
    def __del__(self):
        class_name = self.__class__.__name__
        print(class_name, '销毁')
pt1 = Point()
pt2 = pt1
pt3 = pt2
print(id(pt1),id(pt2),id(pt3))
print(1)
del pt1
print(2)
del pt2
print(3)
del pt3

__del__  # 被调用