Yes it does. x=:(12#0) y=:(1,2,3),(5,6,7),:(9,10,11)
These are equivalent: (x (3 # #\@]) y) (x (,@]) y) } (x ([) y) x (3 # #\@])`(,@])`([) } y Clever On Wed, Jan 28, 2015 at 1:10 PM, Raul Miller <[email protected]> wrote: > Dyadic gerund amend looks like this > > x u0`u1`u2} y > > and works like this: > (x u0 y) (x u1 y)} x u2 y > > (Monadic gerund amend is very different.) > > Does that help? > > Thanks, > > -- > Raul > > > On Wed, Jan 28, 2015 at 12:59 PM, Joe Bogner <[email protected]> wrote: >> On Tue, Jan 27, 2015 at 11:45 PM, Raul Miller <[email protected]> wrote: >>> I guess this is how I'd write that: >>> >>> f=: (3##\@])`(,@])`[} 0 1 2 +/~I. >>> >>> Is that easy enough to read, or should I spell out how it works? >>> >> >> This was enjoyable to decode. It looks simple but there are a few >> things that I haven't used extensively. >> >> I still don't understand the gerund item amend. >> >> Here is my interpretation for others who may be interested >> >> * 1. First I realized it's a hook >> >> I tried using trace and dissect and couldn't figure it out from those >> outputs, so then I tried >> >> (arr f arr) -: (f arr) >> 1 >> >> http://www.jsoftware.com/jwiki/Vocabulary/hook >> >> * 2. Knowing it was a hook I started to break it down >> >> The spacing threw me off a bit initially >> >> NB. gerund amend http://www.jsoftware.com/jwiki/Vocabulary/curlyrt#dyadic >> u=: (3##\@])`(,@])`[ } >> v=: 0 1 2 +/~I. >> >> ((u v) arr) -: (f arr) >> 1 >> >> (arr g (v arr)) -: (f arr) >> 1 >> >> * 3. Item Amend >> >> I haven't yet figured out how this part works >> >> Here's a simpler version to look at >> >> (12#0) ((3 # #\@])`(,@])`[}) ((1,2,3),(5,6,7),:(9,10,11)) >> 0 1 1 1 0 2 2 2 0 3 3 3 >> >> >> The first gerund replicates 3 times the number which corresponds to # >> of rows in the prefix >> >> #\ ((1,2,3),(5,6,7),:(9,10,11)) >> 1 2 3 >> >> The second gerund appears to yield the concatenation >> >> The third gerund yields the left >> >> I don't understand the order these gerunds get applied >> >> The dictionary say: "If m is a gerund, one of its elements determines >> the index argument to the adverb } , and the others modify the >> arguments x and y :"[1] >> >> The phrase that's confusing me is "one of its elements" -- which one? >> >> [1] http://www.jsoftware.com/help/dictionary/d530n.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
