That's a very cool solution, and much quicker than the one based on
progressive index-of. Instead of taking the occurrence count of both x
and y, it just takes the count for x and compares it to the total number
of occurrences in y, given by (#/.~).
Here's a comparison of the two methods. It turns out in the version
based on progressive index-of, the desired verb can be obtained just
from replacing (i.) with (-.) and then using the first column of the
result to select from x, so I've used that version.
NB. Shared verb for occurrence count
oc=: i.~ (] - {) /:@/:
NB. Simplified form of what Roger and I posted
cless1 =: [ {~ [: {."1 #@[ ({. -.&(,.oc) }.) [ i. ,
NB. Tacitized R.E. Boss solution
cless2 =: [ #~ oc@:[ >: (i.~~.) { (#/.~,0:)@]
NB. test data
'a b' =. 500 ({.;~}.) +&(1e5 ?@$ 26)&.(a.&i.) 'a'
10 (6!:2) 'a cless1 b'
0.0178952
10 (6!:2) 'a cless2 b'
0.0063745
a (cless1 -: cless2) b
1
To summarize, here's the fastest solution so far:
oc=: i.~ (] - {) /:@/:
cless =: [ #~ oc@:[ >: (i.~~.) { (#/.~,0:)@]
Marshall
On Mon, Jan 18, 2016 at 03:49:46PM +0000, R.E. Boss wrote:
> I'm getting old, but still remember my solution, improved by Hui:
>
> http://www.jsoftware.com/pipermail/general/2004-May/017503.html
>
> 'abcabbe' strikeb2 'babe'
> cab
>
> Curious how it performs compared to the other solutions.
>
>
> R.E. Boss
>
>
> > -----Original Message-----
> > From: Programming [mailto:[email protected]]
> > On Behalf Of June Kim (???)
> > Sent: maandag 18 januari 2016 5:19
> > To: Programming forum <[email protected]>
> > Subject: [Jprogramming] A Different Less?
> >
> > Hello
> >
> > I am looking for a verb(cless) that does something similar to Less(-.) but
> > counting the elimination, for example:
> >
> > 'abcabbe' -. 'abbe'
> >
> > c
> >
> > 'abcabbe' cless 'babe' NB. get rid of y letters counting the occurrences
> >
> > 'cab'
> >
> >
> > It is easier to define such a verb recursively: 'abcabbe' cless 'babe'
> > equald to 'e' cless~ 'b' cless~ 'a' cless~ 'b' cless~ 'abcabbe'
> >
> >
> > I think recursive definition isn't a usual J-ic approach.
> >
> >
> > How would you implement such a verb elegantly(with which I mean short)?
> >
> >
> > June
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
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