It is much more efficient in time and space to eschew boxing within a column.
On Wed, Oct 23, 2013 at 2:23 PM, Pascal Jasmin <[email protected]>wrote: > I find that using boxed strings in inverted tables avoids a whole series > of issues that occur if you let J fill short strings with pads until they > match length to whatever the longest string is. > > I don't really know how much it slows down things by doing it that way, > but the approach can fix i. by comparing to boxed values. I definitely > don't have an exhaustive list of things that seem harder without boxing > first, but there is probably more than just i. > > > ________________________________ > From: Roger Hui <[email protected]> > To: Programming forum <[email protected]> > Sent: Wednesday, October 23, 2013 4:53:34 PM > Subject: Re: [Jprogramming] a more useful i. ? > > > Thanks. I had not intended to promote rank-deficient arguments. I > probably want to disallow that. > > One effect would be to make > http://www.jsoftware.com/jwiki/Essays/Inverted_Table#Index_of more > immediately useful: If you have to do the overtake yourself for one table, > it's tolerable; if you have to do it on some subset of columns (and you > don't know ahead of time which ones), it's a big mess. Basically in > > tindexof=: i.&>~@[ i.&|: i.&> > > you'd replace the i. in the left and right tines with the I verb that I > defined. > > > > > On Wed, Oct 23, 2013 at 1:45 PM, Henry Rich <[email protected]> wrote: > > > Seems reasonable. This would also promote atoms to match rows of tables. > > I've never needed it. > > > > Henry Rich > > > > > > On 10/23/2013 4:28 PM, Roger Hui wrote: > > > >> Thought experiment: What if i. does overtake on the arguments to ensure > >> that the item shape of the left argument matches the cell shape of the > >> right argument? > >> > >> I=: 4 : '(s{."c x) i. (s{."c y) [ s=. (}.$x)>.(-c=. <:$$x){.$y' > >> x=: > ;:'zero one two five one' > >> y=: > ;:'three one four one five nine' > >> > >> $x > >> 5 4 > >> $y > >> 6 5 > >> > >> x i. y > >> 5 5 5 5 5 5 > >> x I y > >> 5 1 5 1 3 5 > >> ------------------------------**------------------------------** > >> ---------- > >> For information about J forums see > http://www.jsoftware.com/**forums.htm<http://www.jsoftware.com/forums.htm> > > >> > >> ------------------------------**------------------------------** > > ---------- > > For information about J forums see http://www.jsoftware.com/**forums.htm > <http://www.jsoftware.com/forums.htm> > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
