Classes, Objects, Inheritance?

Question

I'm supposed to create three classes: a parent, and child 1 and child 2.
Child 1 and 2 are supposed to inherit from the Parent class. So I believe I've done that.

class Parent:
    """Parent Object"""

    def __init__(self):
        self.greeting = "Hi I'm a Parent Object!"


class ChildA(Parent):

    def __init__(self):
        childclass.__init__(self)
        self.childgreeting = "Hi I'm a Child Object!"


class ChildB(Parent):
    pass

Now I have to write a parent object and the children objects which will print out their respective strings.
That's where I'm getting confused: I already put in the strings that they are a child or parent object within their classes.
But how do I get them to print as an object?

I've started out my code like this.

class Parent(object):

class ChildA(object):

class ChildB(object):

How to get those strings to print is bugging me.
And I have a feeling that my ChildA code for the class is not correct either.

Can anyone help me?

If Parent is indeed a parent, then why do you have ChildA and ChildB inheriting from object? — OneCricketeer
– OneCricketeer, Commented Sep 24, 2016 at 0:44
By the way childclass.__init__ won't work since 'childclass' is not defined — OneCricketeer
– OneCricketeer, Commented Sep 24, 2016 at 0:46
It's supposed to be that Parent has a greeting attribute and childA has a greeting attribute and childB has "pass". After that I'm supposed to create three objects that will print their respective string attributes to the console! — kdkmoment
– kdkmoment, Commented Sep 24, 2016 at 1:02

OneCricketeer · Accepted Answer · 2016-09-24 01:02:39Z

1

Child 1 and 2 are supposed to inherit from the Parent class. So I believe I've done that

Yes, in the first code, you have, but not in the second code.

I have to write a parent object and child 1 and 2 objects that will print out their respective strings

Okay...

p = Parent()
child_a = ChildA()

print(p.greeting) 
print(child_a.childgreeting)

However - ChildA() won't work because __init__ should look like this

class ChildA(Parent):

    def __init__(self):
        super().__init__() # This calls the Parent __init__
        self.childgreeting = "Hi I'm a Child Object!"

Now, the above code will work.

But, I assume you want the greeting attribute to be overwritten? Otherwise you get this

print(child_a.greeting) # Hi I'm a Parent Object!
print(child_a.childgreeting) # Hi I'm a Child Object!

If that is the case, you simply change childgreeting to greeting. Then, from the first example

print(p.greeting) # Hi I'm a Parent Object!
print(child_a.greeting)  # Hi I'm a Child Object!

how do I get them to print as an object?

Not entirely sure what you mean by that, but if you define __str__ to return greeting

class Parent:
    """Parent Object"""

    def __init__(self):
        self.greeting = "Hi I'm a Parent Object!"

    def __str__(self):
        return self.greeting

The example now becomes

print(p) # Hi I'm a Parent Object!
print(child_a)  # Hi I'm a Child Object!

answered Sep 24, 2016 at 1:02

OneCricketeer

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1 Comment

kdkmoment Over a year ago

Yes! This is exactly what I was wondering, brilliantly explained. I'm sorry if my question was a little vague, trying to put it in the best terms I could.

farshed- · Accepted Answer · 2016-09-24 01:02:15Z

0

class Parent(object):

    def __init__(self):
        self.greeting = "Hi I am a parent"
    def __str__(self):
        return self.greeting


class Child(Parent):

    def __init__(self):
        super(Child, self).__init__()
        self.greeting = "Hi I am Child"

    def __str__(self):
        return self.greeting


p = Parent()
print(p)
c = Child()
print(c)

This method could help you to use 'print()' statement to print out greeting for individual class. But if you want to directly get self.greeting attribute you should use

p = Parent()
print(p.greeting)

Hope I understood you since your questions seems to be not properly explained...

answered Sep 24, 2016 at 1:02

farshed-

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1 Comment

kdkmoment Over a year ago

Yes! Thanks for understanding! Sorry it was a little vague!

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