[Tutor] garbage collection/class question

[Mitya Sirenef]

On 01/10/2013 09:06 AM, richard kappler wrote:
> Class is still something I  struggle with. I think I'm finally starting
 > to get my head wrapped around it, but the discussion in a different
 > thread has sparked a question. First, please check my understanding:

 > A class creates objects, it's like a template that allows me to create
 > as many copies as I want of the object but allows me to have slightly
 > different versions of the object by having different values for the
 > variables within the object, which I can set with arguments?

There are good answers already, I just want to address this question;
you are correct but classes allow you to do other things, too. You may
want to use a class even if you don't need multiple instances. Classes
allow you to group related functionality and data together:

class Tree(object):
     height = 0

     def grow(self):
         self.height += 1

You may have a dozen of related functions and you can logically group
them together by making them methods of a class, making it easier to
think about and work on the logic of your program.

Classes also create a namespace for each instance:

x = 1

class A(object):
     x = 2

a = A()

a.x = 3

Here, a.x is completely independent of the global namespace's 'x'. In
instance methods, it can be called with 'self.x' .

There are other things classes provide, but these are the most important
in small / medium size programs. You can read up on OOP here:

http://en.wikipedia.org/wiki/Object-oriented_programming


HTH, - m



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