No, @Ben, it wasn't a question, it was an observation. But questions
arise...
I'm just thinking of Henry's students when they discover this "feature". As
they will... when we've made it easy for them to discover. It's as well to
have our answers ready.
(?.) offers itself as a plug-compatible replacement for (?). But I
anticipate gotchers on that assumption. The differing ranks of monads ? and
?. will have implications under (@) for instance, as well as ("). From a
teaching pov, (?.) may be a rich source of easily grasped counterexamples
to plausible conjectures by beginners.
Thus, in the first year of learning J, I unconsciously conjectured Rank
didn't matter -- for most purposes. You could intuit most problems, ones
that don't emerge much for rank 3 arrays or less. In a lifetime of APL I'd
got away without bothering my head about verb rank.
On Fri, Jan 24, 2014 at 1:38 PM, Ben Gorte - CITG <[email protected]>wrote:
> I see...
>
> In fact your question is why monadic ? has rank 0, instead of _ , which
> would make it like behave more like ?. concerning b. 0 .
>
> We agree that a rank 0 ?. wouldn't be useful:
>
> querydot =: (?.)"0
> querydot (10#100)
> 46 46 46 46 46 46 46 46 46 46
> querydot"1 (10#100)
> 46 46 46 46 46 46 46 46 46 46
>
> Is your question (if it is) not the same sort of question as why +, -, *
> etc. have rank 0?
> Or: what's wrong with:
>
> 11 12 13 +"_ i.3 4
> 11 12 13 14
> 16 17 18 19
> 21 22 23 24
>
> (I don't kow)
>
> Ben
> ________________________________________
> From: [email protected] [
> [email protected]] on behalf of Ian Clark [
> [email protected]]
> Sent: Friday, January 24, 2014 14:18
> To: Programming forum
> Subject: Re: [Jprogramming] ? and ?. have different ranks
>
> It says...
> > Behaves like monadic/dyadic Roll • Deal<
> http://www.jsoftware.com/jwiki/Vocabulary/query>(
> ?) except ...etc.
>
> ...It doesn't. Not with (b.0)
>
>
> On Fri, Jan 24, 2014 at 1:15 PM, Ben Gorte - CITG <[email protected]
> >wrote:
>
> > Looks quite right what is written there.
> >
> > ?."0 (10#100)
> > 46 46 46 46 46 46 46 46 46 46
> > ?. (10#100)
> > 46 55 79 52 54 39 60 57 60 94
> >
> > illustrates that the random seed is always set to the same value (7^5)
> > each time ?. is executed.
> >
> > Ben
> > ________________________________________
> > From: [email protected] [
> > [email protected]] on behalf of Ian Clark [
> > [email protected]]
> > Sent: Friday, January 24, 2014 14:06
> > To: Programming forum
> > Subject: Re: [Jprogramming] ? and ?. have different ranks
> >
> > I'm watching what's being said on this thread, prior to rewriting:
> > http://www.jsoftware.com/jwiki/Vocabulary/querydot
> > Its present wording is wrong.
> >
> > To handle the new rank information, it will need rewriting in
> conventional
> > format. So I have a genuine reason to know why (? b.0) and (?. b.0) are
> > different. :-)
> >
> >
> > On Fri, Jan 24, 2014 at 12:49 PM, Brian Schott <[email protected]
> > >wrote:
> >
> > >
> > >
> > >
> > >
> > >
> > >
> > > Bill,
> > >
> > > To my surprise, you are correct, as the following examples suggest. (My
> > > first reaction was that you were wrong, but that is so rare. )
> > >
> > > ?."+ 3#9
> > > 3 3 3
> > > ?. 3#9
> > > 3 8 8
> > >
> > >
> > > ---
> > > (B=)
> > >
> > > On Jan 24, 2014, at 6:16 AM, bill lam <[email protected]> wrote:
> > >
> > > > I guess this is intended, otherwise all numbers generated will be
> > > identical.
> > > >
> > > > 24.01.2014, в 19:06, Ian Clark <[email protected]> написал(а):
> > > >
> > > >> ? b.0
> > > >> 0 0 0
> > > >> ?. b.0
> > > >> _ 0 0
> > > >>
> > > >> This puzzles me. Apart from the actual numbers they generate, why
> > > shouldn't
> > > >> their behaviour be identical from the user's pov?
> > > >>
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