I was aware that I'd arranged for the central verb to only work on the right-hand side, and I see that here you have corrected that and produced the intended result. This turns out to be what I was reaching toward.
What took me a while to understand is how the left-hand side is interpreted here. I initially envisioned that it must provide the x argument for dn (aka todate) which is defined for zero and one, but not for a date-list (1800 2 5). As you know, it doesn't. In the process of writing this reply it occurred to me that &. must work similarly to u&v so that both arguments independently receive the rightmost transformation. OK, that makes sense. Unfortunately in this case it means that the left-hand argument has to be encoded in a peculiar manner, which runs contrary to the clarity I was reaching for. I'm glad I've improved my sense of how dyadic Under supports both arguments, though. There will come a time where I'll need that, though that time is not now. Thank you very much for the help! On Mon, Mar 9, 2009 at 1:12 PM, R.E. Boss <[email protected]> wrote: > As you can see from > > (((7*[) (+[)&....@] 3&{...@])) > +-------+-------------------+--------------+ > |+-+-+-+|+-------------+-+-+|+--------+-+-+| > ||7|*|[|||+-----+--+--+|@|]|||+-+-+--+|@|]|| > |+-+-+-+|||+-+-+|&.|dn|| | ||||3|&|{.|| | || > | ||||+|[|| | || | |||+-+-+--+| | || > | |||+-+-+| | || | ||+--------+-+-+| > | ||+-----+--+--+| | || | > | |+-------------+-+-+| | > +-------+-------------------+--------------+ > > the central verb Works on the RHS only. > > Perhaps this is what you want? > > 5( ((7 tod...@*[) (+[)&.dn 3&{...@]) , 3&}...@])now > 2009 4 13 11 14 34 > > > R.E. Boss > > > -----Oorspronkelijk bericht----- > Van: [email protected] > [mailto:[email protected]] Namens Tracy Harms > Verzonden: maandag 9 maart 2009 19:48 > Aan: Programming forum > Onderwerp: [Jprogramming] Under > > I'm having difficulty using Under where it seems that it should be > natural to do so. I vaguely recall this difficulty being discussed > here before, but I don't recall the answer. > > load 'dates' > > ]now=: <.6!:0'' > 2009 3 9 11 14 34 > > NB. I can accomplish the desired program as shown below. > wf=: ([: todate (7*[) + todayno@(3&{...@])) , 3&}...@] > 5 wf now > 2009 4 13 11 14 34 > > NB. What I can't do is rely on this relationship > dn =: todayno :. todate > > NB. to rely on Under along these lines: > weeksfrom=: ((7*[) (+[)&....@] 3&{...@]) , 3&}...@] > > NB. However, the left parameter (result of (7*[)) is obscured by the > use of &. (i.e. inaccessible when the addition is to occur) > > Can Under be used in a circumstance like this? > > Tracy > ---------------------------------------------------------------------- > 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
