I understood that that was the context for the sentence. But what I am trying to figure out is whether
> As this appears to be not a decision, it does need a rationale > either. means "As this appears to be a decision in the negative, that negative decision too needs a rationale [which I hope will be forthcoming]." Does it? ----- Original Message ----- From: "R.E. Boss" <[email protected]> Date: Tuesday, August 31, 2010 9:47 Subject: Re: [Jprogramming] Splitting an integer into its digits To: 'Programming forum' <[email protected]> > Probably it's (my) English, not being my native tongue. > I will try to explain. > > > DB: > > If you're wondering why _1 _1 doesn't give the bottom-right > corner of the > > array, like f[0][0] (or maybe f[0;0]) would give the top-left > corner of a > > 2D array in a C-like language, the answer is: in J, compound > > (multi-dimensional) indices are addressed with boxes. > > REB (reaction on this paragraph): > > The only reason for the behavior of { is its rank. So the > answer to "why > > _1 _1 { (NB. the { !(reb)) doesn't give the bottom-right > corner of the > array" > > is: the left hand rank of the dyad { is 0 . > (...) > > So IMO it has nothing to do with "in J, compound (multi- > > dimensional) indices are addressed with boxes". > > DB (continuing): > > There are many ways to present the rationale for this > decision, but an > > easy one is: > > REB (reaction on this paragraph): > > As this appears to be not a decision, it does need a rationale > either. > > Hope this is clear. Sorry if not. > > > R.E. Boss > > > > -----Oorspronkelijk bericht----- > > Van: [email protected] [mailto:programming- > > [email protected]] Namens Roger Hui > > Verzonden: dinsdag 31 augustus 2010 18:00 > > Aan: Programming forum > > Onderwerp: Re: [Jprogramming] Splitting an integer into its digits > > > > I am having trouble parsing your sentence: > > > > > As this appears to be not a decision, it does need a > rationale either. > > > > which immediately follows > > > > > So IMO it has nothing to do with "in J, compound (multi- > > > dimensional) indices are addressed with boxes". > > > > Once I understand what you are saying, perhaps I can > > respond (if a response is required). > > > > > > > > ----- Original Message ----- > > From: "R.E. Boss" <[email protected]> > > Date: Tuesday, August 31, 2010 5:21 > > Subject: Re: [Jprogramming] Splitting an integer into its digits > > To: 'Programming forum' <[email protected]> > > > > > > Van: [email protected] [mailto:programming- > > > > [email protected]] Namens Dan Bron > > > > Verzonden: dinsdag 31 augustus 2010 1:42 > > > (...) > > > > > > > > If you're wondering why _1 _1 doesn't give the bottom-right > > > corner of the > > > > array, like f[0][0] (or maybe f[0;0]) would give the top-left > > > corner of a > > > > 2D > > > > array in a C-like language, the answer is: in J, compound > > > > (multi-dimensional) indices are addressed with boxes. > > > > > > > > There are many ways to present the rationale for this > > > decision, but an > > > > easy > > > > one is: conceptually, a compound index is a single, atomic > > > thing, yet has > > > > structure (this seems contradictory until you work through > > > some examples, > > > > e.g. "the bottom-right corner" of a 2D array). In J, > > > atoms with > > > > (arbitrary) > > > > structure are represented with boxes. Voila. > > > > > > > (...) > > > > > > > > > I disagree with your reasoning. > > > > > > The only reason for the behavior of { is its rank. So the answer > > > to "why _1 > > > _1 { (NB. the { !(reb)) doesn't give the bottom-right corner of > > > the array" > > > is: the left hand rank of the dyad { is 0 . > > > Compare this to dyad {. which has a lh-rank of 1 : > > > > > > _1 _1 {. i.4 5 > > > 19 > > > > > > So IMO it has nothing to do with "in J, compound (multi- > > > dimensional) indices > > > are addressed with boxes". > > > As this appears to be not a decision, it does need a > rationale either. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
