From: Robert Dober <robert.dober@...>
Date: 2007-03-03T04:09:59+09:00
Subject: Re: Hash keys don't work as expected

On 3/2/07, Robert Klemme <shortcutter@googlemail.com> wrote:
> On 02.03.2007 19:28, Tim Hunter wrote:
> > DK wrote:
> >> On Mar 2, 12:58 pm, Tim Hunter <rmag...@gmail.com> wrote:
> >>>> => {[1, 2, 3]=>"test"}
> >>>> DK
> >>> Posted viahttp://www.ruby-forum.com/.
> >> Ah, thank you.  Why is this necessary?  Isn't the lookup just a matter
> >> of matching object_id's?
> >
> > Remember that hash values are distributed into buckets based on their
> > key. Change the key, change the bucket.
>
> More precisely if the hash of the key changes the bucket changes.  And
> since Array calculates it's hash based on the content changing the
> content means changing the key.  And, to the OP, lookups in Hashes are
> not done via #object_id but via #hash:
> http://en.wikipedia.org/wiki/Hashtable
which all is necessary in order to have mutable keys, I guess that it
is very difficult to think about that in the beginning when not yet
used to it.

BTW. I try to avoid to mutate hash keys, I know my limits ;)

Cheers
Robert
>
> Kind regards
>
>         robert
>
>


-- 
We have not succeeded in answering all of our questions.
In fact, in some ways, we are more confused than ever.
But we feel we are confused on a higher level and about more important things.
-Anonymous