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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.

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

Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
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What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
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what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
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I'm interested in nanotube
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Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
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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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