CODEWITHSUNDEEP
python
bob
bob

Reputation: 135

Python - retrieving data from other classes

I have two classes whom I need to be able to talk to each other, mainly one taking data from the other. I omitted everything that was not needed.

class dog(object):
    def __init__(self,name):
        self.name = name
    def getOwner(self):
        return self.name

class shelter(object):
    def getName(self,dogName):
        return dogName.getName()

doggy = dog("Rover")
animalHouse = shelter()

print animalHouse.getName("rover")

The only thing that returns is AttributeError: 'shelter' object has no attribute 'getName'

So how do I go about using the getName function from the dog class inside my shelter class?

Upvotes: 0

Views: 121

Answers (2)

roippi
roippi

Reputation: 25954

Your approach really isn't OOP. What's the point of shelter? You could just invoke getOwner directly on the doggy instance. Think about the physical realities of the objects you're dealing with. You have a dog and a shelter. How does the shelter interact with the dog?

The easiest way is to put one in there. So write that method. Let's give your shelter a resident attribute:

def put(self,dog):
   self.resident = dog

Now, it's best to have your shelter always have that attribute defined, so let's do that in the initializer:

def __init__(self):
    self.resident = None

And while we're at it, let's give ourselves the ability to specify the resident at the time when we create the shelter:

def __init__(self,dog=None):
    self.resident = dog

This is making use of the "default attribute" feature of python. You can specify that argument, or not; it defaults to None if you don't. If this is confusing, you can skip this step.

Given all that (and having put a dog in there), now we have a shelter that contains None or a dog. Let's write your getName method now.

def getName(self):
    if self.resident:
        return self.resident.getOwner() #this method is questionably named, but you wrote it
    else:
        return 'nobody home!'

Other comments: your classes should be named starting with Uppercase letters, and your methods should favor underscores to separate words as opposed to using mixedCase. So Shelter for the class, and get_name for the method. This is according to python naming conventions, see PEP 8 for all the gory details. :)

Upvotes: 0

aIKid
aIKid

Reputation: 28252

You didn't specify the getName function. I think you want to declare getName instead of getOwner in the dog class there, and you need to pass the instance of dog to the function.

class dog(object):
    def __init__(self,name):
        self.name = name
    def getOwner(self):
        return self.name

class shelter(object):
    def getName(self,dogName):
        return dogName.getOwner()

doggy = dog("Rover")
animalHouse = shelter()

And finally:

#Pass the instance!
print animalHouse.getName(doggy)

Upvotes: 1

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