I wrote: > But, if I understand you correctly, you're suggesting Roger > assume 4&$. refers to all SCALAR 1s;
And: > [that] 4&$.^:_1 should produce a two dimensional > boolean array, and both axes should be sparse. I should've said " 4&$.^:_1 should produce a boolean array with the same rank as 4&$. where all axes are sparse" (i.e. not assumed a table). But you know what? Even if you do that, you're still sunk. Remember this thread? http://www.jsoftware.com/pipermail/general/2006-April/026875.html Same problem. Even if you got the rank right viz-a-viz 4&$. , you still don't know the original shape. How long would you make each axis? Now your request for 4&$.^:_1 would have to run something like " s =. 4&$.^:_1 t should produce a boolean array with rank #$t , and shape 1+>./t , with 1s at the atoms specified by (<"1 t) { s and zero elsewhere". Is that really what you want? If you can say all that, isn't it easier just to code: s =. 1 (<"1 t) } 0 $~ 1 + >./ t or any of the other solutions given in this thread? -Dan ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
