OK. I get it: "... so that repeated occurence of an index will produce another function application."
In this particular case also 3 5 3 (+/@(=/) ^&2"0 ]) i.10 0 1 2 81 4 25 6 7 8 9 In general, a=. 1 : '+/@(=/) [EMAIL PROTECTED]:["0 ]' ^&2 a +/@(=/) ^&[EMAIL PROTECTED]:["0 ] 3 5 3 ^&2 a i.10 0 1 2 81 4 25 6 7 8 9 Nice trick with the gerund trains by Dan Bron though. ----- Original Message ---- From: Oleg Kobchenko <[EMAIL PROTECTED]> To: Programming forum <[email protected]> Sent: Saturday, November 25, 2006 10:40:26 PM Subject: Re: [Jprogramming] Index replacement Could the requirements be explained again: how we get from i.10 0 1 2 3 4 5 6 7 8 9 to 0 1 2 81 4 25 6 7 8 9 using 3 5 3? Like this? a^1>.+:+/3 5 3=/a=.i.10 0 1 2 81 4 25 6 7 8 9 ----- Original Message ---- From: JC Coez <[EMAIL PROTECTED]> To: Programming forum <[email protected]> Sent: Friday, November 24, 2006 2:08:48 PM Subject: [Jprogramming] Index replacement How could I apply a function f to elements of an array which are selected by a given list, those elements could be modified several times. For example if f is 2^ and v =: i.10 and ind=: 3 5 3 the result would be 0 1 2 81 4 25 6 7 8 9 I don't find any simple solution. Thanks for any help Jen Claude Coez ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ____________________________________________________________________________________ Do you Yahoo!? Everyone is raving about the all-new Yahoo! Mail beta. http://new.mail.yahoo.com ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ____________________________________________________________________________________ Want to start your own business? Learn how on Yahoo! Small Business. http://smallbusiness.yahoo.com/r-index ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
