Classes and Functions - General Questions

[Bruno Desthuilliers]

Setash a écrit :
> I've got a tiny bit of coding background, but its not the most
> extensive.
> 
> That said, I'm trying to wrap my head around python and have a couple
> questions with classes and functions.
> 
> Two notable questions:
> 
> 1) Classes. How do you extend classes?
> 
> I know its as easy as:
> 
> class classname(a)
>    do stuff
> 
> 
> But where does the parent class need to lie? In the same file? Can it
> lie in another .py file in the root directory? Can it simply be
> accessed via an import statement or just plain jane?
> 
> To clarify, as it may be worded poorly:
> 
> Can my directory structure look like
> 
> ..
> /class1.py
> /class2.py
> 
> And have class2 inherit class1 without any import statements, or need
> it be imported first?
> Or need class1 and class2 be both declared in the same .py file if
> there is inheritance?
> 
> I think thats a bit more clear :)
> 

Any object you want to access must be bound to a name in the current 
namespace. So you either need to define both classes in the same module 
(ie: file), or import the base class. There are some things about this 
in the tutorial...

> 
> 
> 2) Function overloading - is it possible?
> 
> Can I have the following code, or something which acts the same in
> python?:
> 
> 
> def function(a, b)
>    do things
> 
> def function(a, b, c)
>    do things only if I get a third argument
> 

There's no proper function overloading builtin Python [1]. But you have 
default params:

def function(a, b, c=None):
   if c is None:
     do things
   else:
     do things only if I get a third argument


[1] this could be implemented - and is actually implemented (in much 
more powerful way) by Philip Eby's dispatch module.

> Any thoughts / comments / etc? Just trying to get a solid foundation of
> python before going any further.

Then you might want to (re ?)read the tutorial and DiveIntoPython.