[Pythonmac-SIG] string ids

[Sean DiZazzo]

Interesting... It behaves correctly for strings if you use a list inside the
comprehension instead of a tuple.
~Sean

On Mon, Dec 29, 2008 at 7:01 AM, Feat <jf at ai.univ-paris8.fr> wrote:

> I thought a string was stored as a unique object, so why isn't this
> evidenced by the code below ?
>
>        Python 2.5.2 (r252:60911, Feb 22 2008, 07:57:53)
>        [GCC 4.0.1 (Apple Computer, Inc. build 5363)] on darwin
>        >>> [light is 'green' for light in 'green', 'red']
>        [True, False]
>        >>> color = 'green'
>        >>> [light is 'green' for light in 'green', 'red']
>        [False, False]
>        >>> color = 1
>        >>> [light is 'green' for light in 'green', 'red']
>        [True, False]
>
> whereas:
>
>        >>> [x is 1 for x in 1, 2]
>        [True, False]
>
> whether the value 1 is assigned to some other variable or not... the id of
> 1 doesn't vary -- just what is the rationale behind that?
>
> I know I could use the == predicate instead, but just how many different
> greens (with different ids) can  there be, and how do I know which one is
> under focus at a given time?
>
> --
> Jym Feat ~ Paris FR 75018
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