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Define the subclass

The class named Subclass , which extends Superclass , is defined in Listing 2 . This class alsodefines a constructor method named __init__ , which in turn calls the __init__ method of Superclass , passing its own incoming parameters to the superclass constructor method.

Listing 2 . Define a subclass that extends or inherits from Superclass.
#Define a subclass that extends or inherits from Superclass class Subclass(Superclass):def __init__(self,name): Superclass.__init__(self,name)print(self.friend)

The method named __init__ in Subclass also prints the value of the variable named friend when it is executed.

When you instantiate a new object of a class that contains a method named __init__, that method is automatically called and a reference to theobject is automatically passed as the first parameter to the method. However, if you write code that explicitly calls __init__, you must explicitly pass thatparameter along with any other required parameters as shown in Listing 2.

Exercise the classes

The remaining program code is designed to exercise the classes and to illustrate the behavior of inheritance in Python. The code that exercises the classes begins in Listing 3 .

Display the value of the class variable

The code in Listing 3 gets and prints the initial value stored in the class variable named superclassVar , producing the output shown in Figure 1 .

Listing 3 . Display the value of the class variable.
#Code that exercises the classes print(Superclass.superclassVar)

As you can see, at this point in the program, the class variable contains the value True that was placed there when the class variable was created by the code in Listing 1 .

Figure 1 . Output from the code in Listing 3.
True

Instantiate a Subclass object

The code in Listing 4 instantiates an object of the class named Subclass passing "Joe" as a parameter to the __init__ method belonging to that class. (As you will recall, that __init__ method is automatically called when the object is instantiated.)

Figure 2 shows the output produced by executing the code in Listing 4 .

Listing 4 . Instantiate a Subclass object.
ref = Subclass("Joe") print(ref.superclassVar)

As you saw in Listing 2 , the __init__ method in the class named Subclass calls the method named __init__ in the class named Superclass passing both of its incoming parameters as parameters to the __init__ method in the class named Superclass . As you saw in Listing 1 , that method replaces the value True in superclassVar with one of its incoming parameters,which in this case is "Joe" .

The code in the method named __init__ in the class named Subclass in Listing 2 also prints the value of the variable named friend (which is created and initialized by the __init__ method in the class named Superclass in Listing 1 ) . This produces the first line of output text (Tom) shown in Figure 2 .

The code in Listing 4 also uses the reference to the Subclass object to get and print the value of the class variable named superclassVar from the class named Superclass , producing the second line of output text in Figure 2 (Joe) .

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Itse 1359 introduction to scripting languages: python. OpenStax CNX. Jan 22, 2016 Download for free at https://legacy.cnx.org/content/col11713/1.32
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