/* find in Matlab */
/* Notice: Its result is always a column vector. */
new; cls;
x={3,0,0,-1,2};
print find(x);
x={8 1 6,
   3 5 7,
   4 9 2};
print findfirstk(x.>3,4);
print findlastk(x.>3,4);




proc find(x);
   local i,y;
   x=vec(x');
   i=seqa(1,1,rows(x));
   y=(x./=0).*i;
   y=delif(y,y.==0);
   retp(y);
endp;

proc findfirstk(x,k);
   local i,y;
   x=vec(x');
   i=seqa(1,1,rows(x));
   y=(x./=0).*i;
   y=delif(y,y.==0);
   y=y[1:k];
   retp(y);
endp;

proc findlastk(x,k);
   local i,y;
   x=vec(x');
   i=seqa(1,1,rows(x));
   y=(x./=0).*i;
   y=delif(y,y.==0);
   y=y[rows(y)-k+1:rows(y)];
   retp(y);
endp;