When is it a pointer (aka reference) - when is it a copy?

[Steve Holden]

John Henry wrote:
> Hi list,
> 
> Just to make sure I understand this.
> 
> Since there is no "pointer" type in Python, I like to know how I do
> that.
> 
> For instance, if I do:
> 
>    ...some_huge_list is a huge list...
>    some_huge_list[0]=1
>    aref = some_huge_list
>    aref[0]=0
>    print some_huge_list[0]
> 
> we know that the answere will be 0.  In this case, aref is really a
> reference.
> 
> But what if the right hand side is a simple variable (say an int)?  Can
> I "reference" it somehow?  Should I assume that:
> 
>    aref = _any_type_other_than_simple_one
> 
> be a reference, and not a copy?
> 
Yes. Attributes are always object references. The assignment is actually 
the binding of a specific object to a name in some namespace, (r to an 
element of a sequence or other container object.

This applies *whatever* the type of the RHS experession: the expression 
is evaluated to yield an object, and a reference to the object is stored 
in the name or container element.

regards
  Steve
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