> Van: [EMAIL PROTECTED] [mailto:programming- > [EMAIL PROTECTED] Namens Raul Miller > Verzonden: dinsdag 5 februari 2008 13:48 > Aan: Programming forum > Onderwerp: Re: [Jprogramming] Figuring out sums and differences (is it > reallythis simple?) > (...) > I think you should read the definitions of @ @: and [: > > But, basically, > > [: u v > and > u @: v > mean the same thing > > Also, > u @ v > means the same thing as > u @: v "v > > Note that v " v is shorthand for v " (v b. 0) >
Another approach is the following. A verb v produces chunks of data which sometimes are glued together using fills. An example will clarify this. Let i0=: i."0 then i0 2 3 4 0 1 0 0 0 1 2 0 0 1 2 3 whereas (i0 2);(i0 3);i0 4 +---+-----+-------+ |0 1|0 1 2|0 1 2 3| +---+-----+-------+ So i0 is applied to each of the numbers of its right argument y and each of that outputs do have different shape - see inside the boxes - and these outputs are reshaped with fills - 0 in this case - to make one, decent noun. The difference between @ and @: is given by <@:i0 2 3 4 +-------+ |0 1 0 0| |0 1 2 0| |0 1 2 3| +-------+ <@i0 2 3 4 +---+-----+-------+ |0 1|0 1 2|0 1 2 3| +---+-----+-------+ So @: is applied after the glueing is done, @ is applied before the glueing is done. Using <@ or <@: teaches you a lot about the difference. R.E. Boss ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
