From: Teemu Likonen <tlikonen@iki.fi>
To: Thorsten Jolitz <tjolitz@googlemail.com>
Cc: help-gnu-emacs@gnu.org
Subject: Re: Hash tables - how to look up values?
Date: Wed, 04 Jul 2012 17:09:30 +0300 [thread overview]
Message-ID: <871ukrfwit.fsf@imladris.arda> (raw)
In-Reply-To: <873957d4di.fsf@googlemail.com> (Thorsten Jolitz's message of "Wed, 04 Jul 2012 15:48:09 +0200")
Thorsten Jolitz [2012-07-04 15:48:09 +0200] wrote:
> that returns the corresponding key of a known (string) value in a hash
> table (similar to 'rassoc' for alists).
>
> I could not find such a function - does it exist already?
There is no such thing. You need to traverse the hash table with maphash
and look for your value. This is obviously slower than gethash but this
is how hash tables work.
If you need fast two-way access in your programs you could create your
own access functions which synchronize two hash tables and thus get fast
two-way access.
next prev parent reply other threads:[~2012-07-04 14:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-04 13:48 Hash tables - how to look up values? Thorsten Jolitz
2012-07-04 14:09 ` Teemu Likonen [this message]
2012-07-04 14:09 ` Bastien
2012-07-04 14:31 ` Thorsten Jolitz
[not found] <mailman.4023.1341409554.855.help-gnu-emacs@gnu.org>
2012-07-04 13:59 ` Pascal J. Bourguignon
2012-07-04 14:21 ` Thorsten Jolitz
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