In python, subclass inherits the _ init _ Method Instance of the parent class, and python _ init _

In python, subclass inherits the _ init _ Method Instance of the parent class, and python _ init _

Preface

If you have written object-oriented code using Python __init__ The method is very familiar.，__init__Method runs immediately when an object of the class is created. This method can be used to initialize your object.

Note:The start and end of the name are double underscores.

Parent Class

class A(object): def __init__(self, name):  self.name=name  print "name:", self.name def getName(self):  return 'A ' + self.name

Subclass not override__init__ Automatically calls__init__

class B(A): def getName(self):  return 'B '+self.name if __name__=='__main__': b=B('hello') print b.getName()

Run

$python lei2.py name: helloB hello

But it is rewritten.__init__If the subclass is instantiated, the defined__init__

class A(object): def __init__(self, name):  self.name=name  print "name:", self.name def getName(self):  return 'A ' + self.nameclass B(A): def __init__(self, name):  print "hi"  self.name = name def getName(self):  return 'B '+self.nameif __name__=='__main__': b=B('hello') print b.getName()

Run

$python lei2.py hiB hello

In order to use or extend the behavior of the parent class, it is better to display the behavior that calls the parent class__init__Method

class A(object): def __init__(self, name):  self.name=name  print "name:", self.name def getName(self):  return 'A ' + self.nameclass B(A): def __init__(self, name):  super(B, self).__init__(name)  print "hi"  self.name = name def getName(self):  return 'B '+self.nameif __name__=='__main__': b=B('hello') print b.getName()

Run

$python lei2.pyname: hellohiB hello

Summary

The above is all about how python subclass inherits the _ init _ method of the parent class. I hope this article will help you in your learning or work, if you have any questions, you can leave a message.