Here is a quick example with numbers:
list =. /:~ ?.@$~ 100
item =. 19
{: ((,~{.)`(,{:)@.(item > list{~[)~ <.@-:@+/)^:_ ]0,#list
23
list I. item
23
I =: 4 :'{: ((,~{.)`(,{:)@.(y > x{~[)~ <.@-:@+/)^:_ ]0,#x'
list I item
23
(list I. i.100) -: (list I"_ 0 i.100)
1
However, symbols don't compare in the same way, so a binary search isn't
applicable here.
</~ t
0 0 0 0 0 0
1 0 1 1 0 0
1 0 0 0 0 0
1 0 1 0 0 0
1 1 1 1 0 0
1 1 1 1 1 0
Depending on what you are doing, you could re-engineer the items that you
use or just use regular indexing with i. .
Marshall
On Mon, Aug 29, 2011 at 5:03 AM, Steven Taylor <[email protected]> wrote:
> I was looking for an example of power being used for a binary search. Is
> there an example of this in a wiki or a list post?
>
> So far I've ended up with the below, which works well, but originally I was
> aiming at doing a binary search using symbols. Probably there is a
> crossover point where one outperforms the other. I don't need this to be
> super fast right now, but probably it's a good thing to know.
>
> t=.s:'`zero`one`two`three`four`five'
>
> {. I. ; t =/ s:'`three' N.B. take first incase of duplicates. Also, s:
> returns a one item list, hence the need for /
>
> thanks,
> -Steven
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