Python Class Best Practice

[Rod Person]

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On Tue, 04 Dec 2007 15:51:18 -0800
Gary Herron <gherron at islandtraining.com> wrote:
> Rod Person wrote:
> >
> > 1:
> > class Foo(object):
> >   member1=''
> >   member2=0
> >  
> >   def __init__(self,member1='',member2=0):
> >     self.member1 = member1
> >     self.member2 = member2
> >
> > 2:
> > class Foo(object):
> >     def  __init__(self,member1='',member2=0):
> >         self.member1 = member1
> >         self.member2 = member2
> >
> >
> Both examples will store values for member1 and member2 in every
> instance.  Any code that accesses self.member1 (or 2) will get the
> value stored in the instance. 
> 
> Example 1 which also creates two *class* members of the same name
> won't affect the conclusion of the previous paragraph.  The two
> values in the class will be shadowed by each instances members of the
> same name.
> 
> But now I need to ask, what did you expect to happen here? 

Well I guess I should say that I'm coming to Python from Delphi, so I
am used to creating classes like in #1, but I'm used to having to
declare a scope for each member. Not having a scope declaration is
really throwing me some.

> 
>  * If you thought those two extra assignments in example 1 effected
> the execution or storage in the __init__ (or any other method), you
> were mistaken.
> 

Yes, this is what I thought. I thought that declaring member1='' would
just assign the a default value on creation of the class (as in
Delphi). I probably shouldn't have give the parameters in the __init__
a default value in example 1.

> Gary Herron

Thanks. 


- -- 
Rod

http://roddierod.homeunix.net:8080
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