[Jprogramming] Re: Rank and Sort on a Specific Column

[R.E. Boss]

One sort suffices, than index in nub of the sorted items.

R.E. Boss


-----Oorspronkelijk bericht-----
Van: programming-bounces at jsoftware.com
[mailto:programming-bounces at jsoftware.com] Namens Mike Day
Verzonden: maandag 8 mei 2006 15:06
Aan: Programming forum
Onderwerp: Re: [Jprogramming] Re: Rank and Sort on a Specific Column

Not really an improvement,  but the change in "r",
and the idiom for "opent" (cf "line") might be of
interest,  and there are only two sorts.  I don't
think you can manage with fewer sorts!

 lastnum =: {:@".@;@{:@;:&.>  NB. last number in each boxed row
 r =: ] i.~ [:  \:~ ~.  NB. rank (NB. sort applied _after_ nub)
 rankt=:,"0~ <@":@>:@r@:lastnum NB. get & prepend ranks to rows
 opent =: ;:^:_1"1                      NB. better than line???
 tta =: ((\:~@:opent @:rankt))@: (LF& cut)       NB. do the lot

Mike