(0 2$0),i.2 2 0 1 2 3 On Fri, 11 Jan 2013 09:00:42 -0800 Roger Hui <rogerhui.can...@gmail.com> wrote:
> It is not a bug and the following sequence illustrates why the behavior > is > reasonable: > > (n$0) , i. 2 2 [ n=: 3 > 0 0 0 > 0 1 0 > 2 3 0 > (n$0) , i. 2 2 [ n=: 2 > 0 0 > 0 1 > 2 3 > (n$0) , i. 2 2 [ n=: 1 > 0 0 > 0 1 > 2 3 > (n$0) , i. 2 2 [ n=: 0 > 0 0 > 0 1 > 2 3 > > > > On Fri, Jan 11, 2013 at 8:52 AM, Steven Taylor <tayl...@gmail.com> > wrote: > > > I didn't expect this extra (0 0) in the result. > > > > (0 $ 0),i. 2 2 > > 0 0 > > 0 1 > > 2 3 > > > > i.e. nothing prepended to shape equals the same shape (not more or > less) > > > > Is this a bug, or does this make sense in some situations? What > should the > > J way be? > > > > For a simple list, we get my expected behaviour : > > > > (0 $ 0),i. 3 > > 0 1 2 > > > > Here's a possible solution > > > > empty=:(<'') = [: < [ > > > > empty 0 $ 0 > > NB. build result > > (xci sort~ u,xa),ya > > ) > > > > empty=:(<'') = [: < [ > > > > carefulappend=:13 : '(empty x)}. x,y' f. > > > > carefulappend2=:4 : 0 > > if. (empty x) do. > > r=.y > > elseif. empty y do. > > r=.x > > elseif. do. > > r=.x,y > > end. > > r > > ) > > > > (0 $ 0) carefulappend i. 2 2 > > 0 1 > > 2 3 > > > > (0 $ 0) carefulappend2 i. 2 2 > > 0 1 > > 2 3 > > > > thanks, > > -Steven > > --------------------------------------------------------------------- > - > > For information about J forums see > http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
