classes and __init__ question

[Alex Hall]

On 5/17/10, Patrick Maupin <pmaupin at gmail.com> wrote:
> On May 17, 3:19 pm, Alex Hall <mehg... at gmail.com> wrote:
>> Hi all,
>> I am a bit confused about classes. What do you pass a class, since all
>> the actual information is passed to __init__? For example, say you
>> have a dog class. The dog object has a name, a size, and a color. I
>> believe you would say this:
>>
>> class dog():
>>  def __init__(self, name, size, color):
>>   self.name=name
>>   self.size=size
>>   self.color=color
>>  #end def
>> #end class
>>
>> What, then, gets passed to the class constructor?
>> class dog(whatGoesHere?):
>> Sometimes I see things passed to this. For example, if you create a
>> class for a wxPython frame, you will say:
>> class myapp(wx.App):
>> In this case you pass something. However, I have a class that I use in
>> one of my programs to create "contact" objects, which looks like this:
>> class contact():
>>  def __init__(self, name, email, status, service):
>>   self.name=name
>>   self.email=email
>>   self.status=status
>>   self.service=service
>>  #end def
>> #end class
>>
>> Here, I do not pass anything to the class, only to __init__. What is going
>> on?
>>
>> On a related note, is it horrible for resource usage to create a large
>> array, up to 500 or so, where each member is a small object? I am
>> thinking of, for example, a game board array where each member of the
>> array is a "square" object. A square might have a status, a color, and
>> other flags associated with it, so you could then say something like
>> board[i][j].hasGamePiece=True. Lookups and adjustments like this will
>> be going on a lot. Am I better off using an array of numbers where
>> each number means something different?
>>
>> Thanks in advance for any info.
>>
>> --
>> Have a great day,
>> Alex (msg sent from GMail website)
>> mehg... at gmail.com;http://www.facebook.com/mehgcap
>
> What you are calling "passing to a class" is the superclass (or list
> of superclasses) if you are creating a subclass.
So what is a subclass compared to a class? Are you saying that what is
passed to the class, so what is in the parentheses of the class, is
really the superclass? If so, what is the advantage of doing this; why
not just create a class that is not a sub? I thinking I am missing
something elementary here. :)
>
> Under Python 2.x, you might want to subclass object (if you need/want
> a newstyle class), so it is fairly common to see:
>
> class foo(object):
>    whatever
In Java, a class is an object. Is Python the same thing? Would you say
that my dog class, for example, creates a new dog object when an
instance is instantiated?
Thanks.
>
> Regards,
> Pat
> --
> http://mail.python.org/mailman/listinfo/python-list
>


-- 
Have a great day,
Alex (msg sent from GMail website)
mehgcap at gmail.com; http://www.facebook.com/mehgcap