"I'm sure this can be done in a single line using a hook or fork. but I'm not clear enough with the train rules to put this all together on a single line."
One can always ask the tacit translator (if worst come to worst one would get an explicit answer back). 13 : '+/(-.2|a)#a [ a=.>:i.42' [: ([: +/ ([: -. 2 | ]) # ]) (1+i.42)"_ ([: ([: +/ ([: -. 2 | ]) # ]) (1+i.42)"_) _ 462 Its answer can be improved but at least it shows one way to do it, ([: +/ ([: -. 2 | ]) # ]) (1+i.42) 462 etc. The tacit translator was my faithful teacher a long time ago and I still use it occasionally, nowadays to understand non-tacit code. I hope it helps. On Mon, Aug 28, 2017 at 1:02 PM, Skip Cave <[email protected]> wrote: > A simple problem posted on Quora: > > What is the sum of all the even numbers from 2 to 42? > > My J solution: > a=:>:i.42 > +/(-.2|a)#a > 462 > > I'm sure this can be done in a single line using a hook or fork. > but I'm not clear enough with the train rules to put this all together > on a single line. > Any suggestions? > > > > > > Skip Cave > Cave Consulting LLC > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
