python newbie

[Bjoern Schliessmann]

Bruno Desthuilliers wrote:
> Bjoern Schliessmann a écrit :

>> You can't just declare in Python, you always define objects (and
>> bind a name to them).
> 
> def toto():
>    global p
>    p = 42
> 
> Here I declared 'x' as global without defining it.

Ah well, someone had to notice it ...

BTW, where's x? :)
 
>> Yes, globals need to be defined before you
>> can access them using "global".
> 
> For which definition of 'defined' ?

to define a name: to bind an object to a name
 
>  >>> p
> Traceback (most recent call last):
>    File "<stdin>", line 1, in <module>
> NameError: name 'p' is not defined
>  >>> toto()
>  >>> p
> 42
>  >>>

Easy, p = 42 is a definition. 

That's also true for translating to C/C++ nomenclature
where "declare" means "tell the compiler a name and its type"
and "define" means "declare and reserve memory for it".

> Hem... I'm not sure you're really addressing the OP's question
> here. 

Me too ...

> But anyway: in Python, everything's an object, so the only 
> thing that makes functions a bit specials is that they are
> callable - as are classes, methods, and every instance of a class
> implementing __call__ FWIW. So saying 'variables holds data,
> functions do stuff' is unapplyiable to Python.

I don't think so. Even if everything is an object, there is still a
concept behind the words "function" and "variable".
 
>> They are.
> 
> functions are *not* methods of their module.

Yes, I used the term very sloppily. At least they are attributes.

Regards,


Björn

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