Both this approach and Raul's appear to answer your requirement, but I'm
wondering
what result you require for this slightly altered input:
l1 =: 0 _1 0 1 2 _1 4 5 _6
If you need maximally contiguous runs, I'd have thought this would be a
preferred solution:
0 ; _1 0 1 2 ; _1 ; 4 5 ; _6
┌─┬────────┬──┬───┬──┐
│0│_1 0 1 2│_1│4 5│_6│
└─┴────────┴──┴───┴──┘
since the run _1 0 1 2 is of length 4.
However, both suggested methods return this
(<;.1~ (~:_,}:)@p) l1 NB. xash
┌─┬──┬─────┬──┬───┬──┐
│0│_1│0 1 2│_1│4 5│_6│
└─┴──┴─────┴──┴───┴──┘
p F l1 NB. RM
┌─┬──┬─────┬──┬───┬──┐
│0│_1│0 1 2│_1│4 5│_6│
└─┴──┴─────┴──┴───┴──┘
I suppose my problem is that I don't see the point of property p !
Cheers,
Mike
On 07/01/2021 09:29, xash wrote:
l =: _1 _2 0 1 2 _1 4 5 _6
p =: <&0
(<;.1~ (~:_,}:)@p) l
┌─────┬─────┬──┬───┬──┐
│_1 _2│0 1 2│_1│4 5│_6│
└─────┴─────┴──┴───┴──┘
On Thu Jan 7, 2021 at 10:12 AM CET, Justin Paston-Cooper wrote:
I am sure this has been asked and formulated somewhere else. I don't
know what the name of it is.
Let G be a set of groups. Given a list `l =: l_1 ... l_2` and a
property `p` such that `p l_i` is in G, I would like a function `f`
which partitions `l` into the successive maximally contiguous runs
`r_1 ... r_k` such that for each `i`, `r_i` is a substring of `l`,
there exists one `g` in G such that all `p r_ij = g` and the
concatenation of `r_1 ... r_k` is equal to the original `l`.
Examples:
l = _1 _2 0 1 2 _1 4 5 _6`
p = <&0
f l = _1 _2 ; 0 1 2 ; _1 ; 4 5 ; _6
;. gets close, but one would need to specify where groups end possibly
by comparing successive pairs of applications of `p`. Those positions
would somehow need to be indicated as frets.
/. gets close, but concatenates separate runs within the same group.
Is this trivial, or should I write my own code for this?
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
