Note that (#~/@:|:) is a much faster inverse.
Marshall
On Mon, Jun 29, 2015 at 04:22:08PM +0000, 'Pascal Jasmin' via Programming wrote:
> pretty much the same as the rosettacode solution, but focused on an internal
> representation rather than outputting a string
>
> torle =: (1 ,~ 2&(~:/\)) ({. , #);.2 ]
> frle =: ([: ; <@#~/"1) :.torle
>
>
>
> ----- Original Message -----
> From: Raul Miller <[email protected]>
> To: Programming forum <[email protected]>
> Cc:
> Sent: Monday, June 29, 2015 12:04 PM
> Subject: Re: [Jprogramming] integer run length compression
>
> Perhaps http://rosettacode.org/wiki/Run-length_encoding#J
>
> Thanks,
>
> --
> Raul
>
>
> On Mon, Jun 29, 2015 at 11:55 AM, John Baker <[email protected]> wrote:
> > I vaguely remember reading forum traffic sometime ago about a simple
> > J based run length encoding verb for integers.
> >
> > eg:
> >
> > If you have list of integers with many runs of the same value.
> >
> > 0 0 0 0 0 0 2 4 4 4 4 2 0 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 0 2
> > 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> >
> > What's a good way to compress, and decompress, this using only J?
> >
> > Just thought I would ask before rolling my own.
> >
> > --
> > John D. Baker
> > [email protected]
> > ----------------------------------------------------------------------
> > 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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