Understanding Class Inheritance in Python from learningPythonthehardway -

I am learning python and I understand what is meant by inheritance between classes and objects. So here is my code, I want to make sure that I got it right below:

  class animal (object): def __init __ (self, name): self.name = name print Self.name def armor (self, name): print "eh% s"% name class dog (animal): def __init __ (self, name): ## - a __init__ function that takes the name and name parameter itself. Self. Name = name print "% s is bark and happy"% self.name def sound (self, name): print "% s bark"% name Rover = dog ("rover") rover. Sound ("rover") rover. Hole ("rover")  

To better understand that my class behaves with "base class" animal , I put print Given everywhere and I can see that dog is capable of calling howl , a function from its original class, animal (Is that correct?)

My second question was: How do I use it when I use the rover = dog ("rover") Code> __init __ function type The answer is not it? What is the purpose of a __init __ function when it is actually set to a value for each variable ( self.name )? Because no call rover .__ init __ ("rover") does not , and you can not print print (rover = dog ("rover")) and why No __ init __ print out of the animal class?

The class is just asking for clarification on function behaviors between succession and related classes.

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1 dog

Animals (Is that correct?)

Yes, you are right. Since you have declared dog class to be inherited by animal - class dog - the dog All properties in the class - including methods - have been declared in Animals , so you can call howl on a dog.

2 When I use the rover = ("rover") , how it uses the __ init __ function call

When ClassName (& lt; Parameters & gt;) What is happening behind the scenes, among other things, is that Python __ Init __ will define the method in class className . To see more details, which also indicates why without a class __init __ method will call your parent's __init __ method. This documentation also answers your sub question What is the purpose of a __ init __ function ... ? The overall idea is that you (almost) never call directly to the __init __ method.

Now for the fun part!

3 Why did ' Animal print out of class

__init __ method Animals are almost identical to and dogs i.e. set the name attribute and print something. The only difference is what they print. So let's say that you want to write your classes in such a way:

  class animal (object): def __init __ (self, name): self.name = name print "I have a name called% s The soul is the animal. "Self.name class dog (animal): def __init __ (self, name): super (dog, self) .__ init __ (name) # This important line is printed" I actually name a dog% S, I bark too! " % Self.name Rover = Dog ("Rover") # Output: #I am a creature named Rover # I am a dog named Rover, I also spit!  

As is commendable, when we see super (dog, self) .__ init __ (name) - see - it will retrieve the super line Dog and then we call the __init __ method to start the current object self - hence the name Setting and code in < Animal category> Print Statement.

Calls are ended, note that you have __ init __ of the super class:

  animal .__ init __ (self, name) super (dog) , Itself) .__ init __ (name) super (self .__ class__, itself) .__ init__ (name) # self__ class__ is self or its type of class  

different syntax See more than in depth.