Can Python function return multiple data?

[Alain Ketterlin]

Marko Rauhamaa <marko at pacujo.net> writes:

> Alain Ketterlin <alain at universite-de-strasbourg.fr.invalid>:
>
>> Grant Edwards <invalid at invalid.invalid> writes:
>>
>> [...]
>>> Or to be a bit obtuse: Python parameters are passed by value, but all
>>> values are references.
>>
>> Exactly, that's a perfect description. There's is no need for a new
>> name. As a corollary, all names (including "variables" and object
>> attributes) are references.
>
> We are all confusing each other because of the word "reference" means so
> many things.
>
> In Grant's explanation, a "reference" is a pointer, the invisible gluons
> that bind, say, a variable to an object.
>
> In Alain's sentence a "reference" is a variable or any other "lvalue"
> that can be bound to an object.
>
> Thus, the statement
>
>     a[3] = 4
>
> contains the reference[Alain] "a[3]". After the statement is executed,
> the reference[Alain] contains a reference[Grant] to an int object 4.

You're right, my wording is imprecise, your interpretation is absolutely
correct.

> Now, is it useful to make the distinction and use the verb "contain?"
>
> Yes, it is. Consider these statements:
>
>     a[0] = 4
>     a[1] = 4
>     a[2] = a[1]
>
> Now, "a[0]", "a[1]" and "a[2]" are three separate references[Alain].
> However between the three, they contain a maximum of two distinct
> references[Grant], which can be ascertained with an "is" test:
>
>     a[2] is a[1]
>     => True
>
> So while the references[Grant] are identical, the references[Alain] are
> not. If I'm not mistaken, Python has no means of comparing the
> identities of references[Alain].

Right.

-- Alain.