Dual look-up on keys?

[castironpi at gmail.com]

On Mar 5, 4:00 pm, Grant Edwards <gra... at visi.com> wrote:
> On 2008-03-05, castiro... at gmail.com <castiro... at gmail.com> wrote:
>
> >>>>> I want to hash values to keys.  How do the alternatives compare?
>
> >>>>http://catb.org/~esr/faqs/smart-questions.html
>
> >>> ... without extending the whole way to a full relational database?
>
> >> You didn't bother following the link and reading the advice, did you? If
> >> you did, you haven't done a good job of following that advice.
>
> > Well, obviously there's someone who's interested in computers and
> > programming that has a question.
>
> It may be  obvious that he has a question.  It's not the least
> bit obvious what that question is.
>
> > Communication is not his forte, but effort, willingness,
> > devotion, and dedication are.  What should he do, and what
> > should the others, who are gifted speakers?
>
> He should spend less time trying to generate "gifted speach"
> and more time learning how to ask an understandable, meaningful
> question.  The link which you ignored explains how to do that.
>
> In your original post, it's not very clear what you mean by
> "hash values to keys" means nor what alternatives you're asking
> about. If you're trying to learn about hashing algorithms, then
> google "hashing algorithms" and read the first half-dozen hits.
>
> The first two are Wikipedia articles which are both quite good
> and are almost certainly available in your native lanauge.
>
> --
> Grant Edwards                   grante             Yow! But they went to MARS
>                                   at               around 1953!!
>                                visi.com            

Are you vegetarian?  A little off topic.

Anyway, if (a,b) is a key in dictionary d, can it guarantee that (b,a)
is also in it, and maps to the same object?