On Wed, Oct 2, 2013 at 9:45 AM, Pascal Jasmin <[email protected]> wrote: > I guess that I should completely understand why $2 is not 0 > or 1, but I can let my pretty little head just consider that a list > of 1 and a scalar must be different:
Yes. In J, */$n must give the number of elements in ,n and */$$n must give the number of dimensions in n (which is also the number of elements in $n). If $2 were 0 then 2 could not contain the value 2. If $2 were 1 then 2 would have one dimension and be a list containing the value 2 instead of just being the value 2. Put differently, Iverson's approach (illustrated above) is to traditional math something like what arabic numerals were to roman numerals. It takes some time to get comfortable with reasons for representing "nothing" (and different flavors of nothing) but once you have grasped this kind of approach you are then faced with painful tedium when trying to do what you now feel is simple, when using the long winded arbitrarinesses of the older contrivances. Note also that J is not unique here. Thanks, -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
