to get the oneliner, use the f. adverb eg (#~ special) f. digits should be used as rank 0, and the @ adjacent to digits should then be changed @: otherwise fp1 and +/ would also become used as rank 0.
or you want a spoiler? Сбт, 28 Авг 2010, Alex Gian писал(а): > Hi all, > > OK, based on the understanding I've gained so far, here and on the other > thread (re filtering), I thought I'd try a couple of little tests, see > how I get along. > > I've got two here, the first is a quasi trivial programming challenge > (it was originally given for programmable calculators) and is fairly > easy in concept. The second one is the so-called "happy numbers" which > I found quite simple to do, but I may still ask for some style feedback. > > First off, the "challenge". It's quite simple in concept, and I know > how to do all the separate bits in J, but I'm having trouble stringing > it all coherently. I get "length errors", which makes me suspect rank. > > The challenge: > We define a 'special' number as one which returns itself when subjected > to the following operation: first split it into its digits, then > perform the following operation on each digit x: x! + x > Then sum the result. > Required to find all special numbers between 1 and 100000 (I think there > are two) > > Here's what I got so far. Not nearly brave enough to put it on one line > yet. > > digits =. 10&#.inv NB. No probs here > fp1 =. ! + ] NB. I think that's fine too > spsum =. +/ @ fp1 @ digits NB. Works... BUT... > special=. ]=spsum > (#~ special) >:i.1000000 NB. That's the idea, but it's wrong > > I think the problem is with spsum, above. > it will not process arrays correctly, although it's fine with single > numbers. > > And if anyone feels like depriving me of sleep, please write down the > single line expression... > > > > > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm -- regards, ==================================================== GPG key 1024D/4434BAB3 2008-08-24 gpg --keyserver subkeys.pgp.net --recv-keys 4434BAB3 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
