On Feb 4, 2014, at 5:29 AM, Raul Miller <rauldmil...@gmail.com> wrote:
> > Of course you will also get an error if you try to combine one of > those with another array of the wrong shape. Error conditions are one > of the cases where I like getting the shapes of arrays. > Sometimes the zeros can affect the result even though they can't be seen in the display $ ( 0 2 3 $ 4), 5 7 $5 1 5 7 $ (0 0 2 3 $ 4), 5 7 $5 1 1 5 7 I am looking for ways to give the programmer some 'leverage' into these situations by the ways that shapes are displayed > One of my favorite tricks, if I am getting an error from an expression > that seems to be due to of a lack of shapeliness (like a length error) > is to replace the last verb with $ (or a variation like ;&$ or $&.> or > ;&($ L:0) or whatever else). > > And that brings up another issue related to finding the shapes of > things: the shape inside a box will typically be different from the > shape outside the box (these shapes are "independent" of each other). Yep, I am working on boxes at the moment and it is a challenge for display while retaining the independent shape of contents. > Also, the shape of transitory arrays (intermediate results) can also > matter. So familiarity with debugging tools and techniques can be > crucial - sometimes even more important for coding than familiarity > with shape and rank issues. (These are not, properly speaking, a part > of the language itself so much as they are a part of the environment. > But that's something of a technicality.) No doubt. Display can't replace knowing how rank and shape work. I am hoping that a little better way of displaying results will make it easier to see the differences and may emphasize the importance of understanding the concepts to those learning the language - that would be me! Cheers, bob ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
