Thank you bob and raul. I knew I was overlooking something simple. I'll read through that section of J for C again
On Tue, Aug 12, 2014 at 6:54 PM, Raul Miller <[email protected]> wrote: > That (using /.) is what I was going to say. > > > S > > p > > o > > i > > l > > e > > r > > > > S > > p > > a > > c > > e > > . > > . > > . > > ({."1 ]/. {:"1) a,b > > Thanks, > > -- > Raul > > On Tue, Aug 12, 2014 at 6:36 PM, robert therriault > <[email protected]> wrote: >> Hi Joe, >> >> Henry touches on this in JforC: Apply On Subsets: Dyad u/. >> >> http://www.jsoftware.com/help/jforc/loopless_code_v_partitions.htm#_Toc191734451 >> >> He does a total instead of an append, but I think you'll get the idea. >> >> Cheers, bob >> >> On Aug 12, 2014, at 3:19 PM, Joe Bogner <[email protected]> wrote: >> >>> I've been fiddling with this for 30 minutes and I can't figure it >>> out... Maybe it's too late in the day >>> >>> a=:_2]\'a';1;'b';2;'c';3 >>> b=:_2]\'c';5;'a';4 >>> >>> what verb will produce this? >>> >>> ]a,.(4;'';5) >>> ┌─┬─┬─┐ >>> │a│1│4│ >>> ├─┼─┼─┤ >>> │b│2│ │ >>> ├─┼─┼─┤ >>> │c│3│5│ >>> └─┴─┴─┘ >>> >>> >>> I went down this path: >>> >>> ] ((0{"1 b)i.(0{"1 a)) >>> 1 2 0 >>> >>> I figured I could use { and return '' if the index was greater than >>> the length (e.g., 2 should be '') >>> >>> I tried using :: to return '' on index error but I couldn't get that to work >>> >>> NB. not what I wanted >>> ] ((0{"1 b)i.(0{"1 a)) ({ :: ('no'"_)) b >>> no >>> >>> Then I tried using ^: to return '' if the length was greater than # b >>> >>> Then I tried writing a explicit verb using if. >>> >>> Then I threw in the towel and decided to ask for help since this must >>> be a common need >>> >>> I'm sure I've solved this before but cannot remember how >>> ---------------------------------------------------------------------- >>> 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
