From: Robert Klemme <bob.news@...>
Date: 2004-09-04T18:35:50+09:00
Subject: Re: Hashes and ordering


"Kristof Bastiaensen" <kristof@vleeuwen.org> schrieb im Newsbeitrag
news:pan.2004.09.04.07.58.02.69935@vleeuwen.org...
> On Sat, 04 Sep 2004 12:39:31 +0900, Hal Fulton wrote:
>
> > Markus wrote:
> >> Where are you going with this?  There seem to be three unrelated things
> >> here:
> >
> > Well, I have been thinking along the lines of: What if we had a built-in
> > ordered indexable collection in Ruby?
> >
>
> What about an association list (Array)?
>
> [["one", 1], ["two", 2], ["three", 3]].assoc("one")
> => ["one", 1]
>
> You could wrap it in a class to have it behave more like a Hash.

Very inefficient if you have many lookups (O(n)).  And it doesn't maintain
order automatically.

The typical and most efficient implementation in the general case of an
ordered map is a tree AFAIK.

Kind regards

    robert