Python destructor and constructor usage explained

Class Test (object):    def __init__ (self, name):        self.name = name        print (' This is the constructor ')    def Say_hi (self):        print (' Hell,%s '% self.name)    def __del__ (self):        print (' This is destructor ') obj = Test (' Bigberg ') Obj.say_hi () del obj #输出 This is the constructor Hello Bigberg this is a destructor

　　

constructor function

Used to initialize the contents of the class state, Python provides a constructor-style __init__ (), that is, when the class is instantiated to execute the function, the __init__ () method is optional, if not provided, Python will give the default __init__ method.

Destructors

"__del__" is a destructor, when using Del to delete an object, it will call his own destructor, in addition, when the object is called in a scope, the destructor will be called once when it jumps out of its scope, which can be used to free memory space.

__DEL__ () is optional, and if not provided, Python provides default destructors in the background

If you want to explicitly call a destructor, you can use the DEL keyword: del obj garbage collection Mechanism 　　

s = ' 123 ' Print (' del ... Running ') del s

When we delete an object with Del, we do not actually clear the object's memory space directly. Python uses the ' reference count ' algorithm to handle recycling, which means that when an object is no longer referenced by another object within its scope, Python automatically clears the object.

The destructor __del__ () automatically clears the memory space of the deleted object when it is referenced.

constructor function:

Used to initialize the contents of the class state, Python provides a constructor-style __init__ ();

That is, the function is executed when the class is instantiated. Then we can put the attributes that we want to initialize first into this function. The following programs:

The __init__ () method is optional and if not provided, Python gives the default __init__ method

Get and set methods for general data acquisition need to be defined