And in ancient days it was done in APL as: y=: 3 5 2 (i.+/y) - y#}:+/\0,y 0 1 2 0 1 2 3 4 0 1
----- Original Message ----- From: Roger Hui <[EMAIL PROTECTED]> Date: Thursday, September 11, 2008 6:54 Subject: RE: [Jgeneral] Verb Sequences - u@:v and [EMAIL PROTECTED] To: General forum <[email protected]> > I get your point but to do it literally without @ you can do: > > ;@:(i.&.>) > > > > ----- Original Message ----- > From: Henry Rich <[EMAIL PROTECTED]> > Date: Thursday, September 11, 2008 6:10 > Subject: RE: [Jgeneral] Verb Sequences - u@:v and [EMAIL PROTECTED] > To: 'General forum' <[email protected]> > > > Ric gave the example I thought of (change 'first item' > > to 'last item' in the example). > > > > Generally you need @ when your verb has to have > > rank other than _ . > > > > Try this: create a verb that produces a sequence of > > index vectors for the atome of its input, by which I mean > > > > v 3 5 2 > > 0 1 2 0 1 2 3 4 0 1 > > > > Using @ you have > > > > v =: ; @: (<@i."0) > > > > I can do it without @ but I don't think I'd want to. > > > > Henry Rich > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] > > > [mailto:[EMAIL PROTECTED] On Behalf Of Alex Rufon > > > Sent: Thursday, September 11, 2008 4:10 AM > > > To: General forum > > > Subject: [Jgeneral] Verb Sequences - u@:v and [EMAIL PROTECTED] > > > > > > Hi. > > > > > > I'm at Chapter 12 of J for C Programmers and Henry was > > explaining verb > > > sequences. > > > > > > You see, I have never ever used @: or @ in my years of use > of > > > J so this > > > is a bit confusing for me. > > > > > > Like in the example on page 111 where it defines: > > > ]a=: 1 2 3; 4 5; 6 7 8 > > > +-----+---+-----+ > > > |1 2 3|4 5|6 7 8| > > > +-----+---+-----+ > > > > > > The requirement was remove the first box and just get the > > > first items of > > > the succeeding boxes. The solution that was provided was: > > > }.@:({.@>) a > > > 4 6 > > > > > > Since I've don't use "Verb Sequences", my solution was: > > > }. {. "1 > a > > > 4 6 > > > > > > I tried doing the other samples and I can still come up with > > solutions> without using the @ and @: symbols. > > > > > > So I am wondering if anybody has good examples where I would > > > absolutely > > > need to use verb sequencing so I can compromise with myself > > when to > > > properly use the symbols. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
