Yes, without reading what you are saying too closely, my point was that more than one thing can return the same printed representation and without a scholarly knowledge of J, one might conclude one is getting the same thing back.
On 4/4/07, Dan Bron <[EMAIL PROTECTED]> wrote:
>a lot of J must be taught - when the representation for an empty list >and a rank-1 array of shape 0 are both blank lines... The display should be the same: a rank-1 array of shape ,0 _is_ an empty list. If we use the narrower definition of list given in http://www.jsoftware.com/help/dictionary/dicta.htm : 1120 77 qdoj 'dicta' NB. Section A: Nouns Arrays of ranks 0, 1, and 2 are also called atom, list, and table Then _only_ rank-1 arrays of shape ,0 are empty lists. If we use the broader sense of list, as in "every array is a list of items", then any array with 0 items an empty list. But then, not all arrays with tally zero display the same way: < i. 0 ++ || ++ < i. 0 0 ++ ++ (the boxes just make obvious the difference in display) That is, empty rank-1 arrays display 1 blank line, empty not-rank-1 arrays display 0 (blank) lines. Here, empty means "no items", not "no atoms". Some arrays with items but no atoms (zero volume) display blank lines: < i. 1 0 ++ || ++ The justification for this is that a rank-1 array is one line; one line with no 0-cells is a blank line. A higher ranked array has one line for each of its 1-cells. No 1-cells means no lines. A higher ranked array with 1-cells but no 0-cells has 1 blank line per 1-cell. -Dan ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
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