Re: Second output argument for setdiff

[Marco Caliari]

OK, please try the following instead

if (iscellstr (a))
  [sorta,idxa] = sort(a(:));
  idx = idxa(find(any(strcmp(repmat(sorta(:)',size(c,1)*size(c,2),1),...
        repmat(c(:),1,size(a,1)*size(a,2))))));
else
  [sorta,idxa] = sort(a);
  idx = idxa(find(any(repmat(sorta(:)',size(c,1)*size(c,2),1) ==...
        repmat(c(:),1,size(a,1)*size(a,2)))));
endif
[y,iy] = unique(a(idx));
i = reshape(idx(iy),size(c,1),length(idx(iy))/size(c,1));

with the following test

[c,i]=setdiff({"two","two";"three","four"},{"one","two";"three","six"})

i should be 4.

Marco

> Am Dienstag, den 15.04.2008, 16:33 -0400 schrieb John W. Eaton:
> > On 15-Apr-2008, Marco Caliari wrote:
> >
> > | Dear maintainers,
> > |
> > | first of all, my apologizes for not sending a hg patch.
> > | The following code
> > |
> > | [sorta,idxa] = sort(a);
> > | idx = idxa(find(all(repmat(sorta(:)',size(c,1)*size(c,2),1)-...
> > |        repmat(c(:),1,size(a,1)*size(a,2))) == 0));
> > | [y,iy] = unique(a(idx));
> > | i = reshape(idx(iy),size(c,1),length(idx(iy))/size(c,1));
> > |
> > | put at the end of setdiff.m (Octave 3.0.1b) will return i such that c =
> > | a(i) (or c = a(i,:)). I checked the behaviour vs. Matlab with the following
> > | script
> > |
> > | clear all
> > | disp('easy')
> > | a = [10 20 30 40]
> > | b = [20 40]
> > | [c,i] = setdiff(a,b)
> > | disp('unsorted')
> > | a = [40 20 30 10]
> > | b = [20 40]
> > | [c,i] = setdiff(a,b)
> > | disp('double entries')
> > | a = [40 40 20 30 10]
> > | b = [20 40]
> > | [c,i] = setdiff(a,b)
> > | disp('rows')
> > | A = [10 20;30 40;50 60;30 40];
> > | B = [10 20];
> > | [C,I] = setdiff(A,B,'rows')
> > |
> > | It would be nice to have this feature included in the next Octave release.
> >
> > Would someone please turn this into a patch that includes tests?
>
> Not possible, after including the attached patch:
>
> ===============================================================================
> > test setdiff
>  ***** assert(setdiff({"one","two";"three","four"},{"one","two";"three","six"}), 
> {"four"})
> !!!!! test failed
> error: binary operator `-' not implemented for `cell' by `cell' operations
> ???===============================================================================
>
> I didn't look into it further.
>
>         Thomas