Yes. Nicer to fix the issue at source.
On Wed, Jun 8, 2016 at 10:34 AM, Raul Miller <[email protected]> wrote:
> Here's how I would handle the empty result case:
>
> mergeMask=: [: ;@(+/\@(0 1&E.) <@(* ~:/\)/. ]) -@# {. 2 =/\ ]
>
> (mergeRow remains unchanged)
>
> Thanks,
>
> --
> Raul
>
> On Tue, Jun 7, 2016 at 6:10 PM, Ric Sherlock <[email protected]> wrote:
> > Thanks that's much nicer.
> > The only case it doesn't handle is the empty arg (which I didn't put in
> my
> > spec!).
> >
> > mergeRow i.0
> >
> > |length error: mergeRow
> >
> > | mergeRow i.0
> >
> >
> > A quick fix:
> > mergeRow=: ((-.@] # [ (+/@:{~ <:,:])`(<:@])`[} I.@]) mergeMask) ::
> ((i.0)"_)
> >
> > $mergeRow i.0
> >
> > 0
> >
> >
> >
> >
> >
> > On Wed, Jun 8, 2016 at 9:29 AM, Raul Miller <[email protected]>
> wrote:
> >
> >> Best I can think of is something like this:
> >>
> >> mergeMask=: [: ;@(+/\@(0 1&E.) <@(* ~:/\)/. ]) 0, 2 =/\ ]
> >> mergeRow=: (-.@] # [ (+/@:{~ <:,:])`(<:@])`[} I.@]) mergeMask
> >>
> >> Hopefully that makes sense?
> >>
> >> Thanks,
> >>
> >> --
> >> Raul
> >>
> >>
> >> On Tue, Jun 7, 2016 at 5:15 PM, Ric Sherlock <[email protected]> wrote:
> >> > I'm looking for a J-like approach to a verb for merging adjacent
> numbers
> >> in
> >> > a row where the numbers are the same. For example
> >> >
> >> > mergerow 4 4 4 4
> >> >
> >> > 8 8
> >> >
> >> > mergerow 8 8
> >> >
> >> > 16
> >> >
> >> > mergerow 16
> >> >
> >> > 16
> >> >
> >> > mergerow 4 4 4
> >> >
> >> > 8 4
> >> >
> >> > mergerow 8 4
> >> >
> >> > 8 4
> >> >
> >> > mergerow 4 8 8 4
> >> >
> >> > 4 16 4
> >> >
> >> >
> >> > My version below which I've used as part of the answer to a
> RosettaCode
> >> task
> >> > <http://rosettacode.org/wiki/2048#J> is very non J-like:
> >> >
> >> > mergerow=: verb define
> >> > len=. <:@# y
> >> > row=. i. i=. 0
> >> > while. (i <: len) *. len >: 0 do.
> >> > if. =/ (i , i+1) { y,_9 do.
> >> > row=. row, +: i { y
> >> > i=. i + 2
> >> > else.
> >> > row=. row, i { y
> >> > i=. i + 1
> >> > end.
> >> > end.
> >> > row
> >> > )
> >> >
> >> > I thought I had a good solution with:
> >> >
> >> > mergerow=: rplc (2&# ; +:)&>@~.
> >> >
> >> > But this seemed to cause unpredictable behaviour when used as part of
> the
> >> > whole solution.
> >> > ----------------------------------------------------------------------
> >> > For information about J forums see
> http://www.jsoftware.com/forums.htm
> >> ----------------------------------------------------------------------
> >> For information about J forums see http://www.jsoftware.com/forums.htm
> > ----------------------------------------------------------------------
> > 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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For information about J forums see http://www.jsoftware.com/forums.htm
