Regarding 0-origin and 1-origin indexing. It helped me to mentally distinguish
between cardinal numbers, 0 1 2 3 . . . , pronounced "zero", "one", "two",
"three", and so on, and ordinal numbers, 1 2 3 4 . . . , pronounced: "first",
"second", "third", "fourth", and so on, or alternatively "number one", "number
two" and so on. Obviously the first element should be number one. rather than
number zero. But the cardinal number zero is the number of elements to be
skipped before you reach the element in question. This cardinal number can be
used as an index, but it is not an ordinal number. So 0-origin indexing is nice
for computing, but it should not be confused with counting. The first element
is the "skip zero" element, but not the zeroeth element.
Thanks. Bo.
Den 0:27 fredag den 18. maj 2018 skrev Ian Clark <[email protected]>:
> Sorry if any of these questions are perceived to be offensive, probably
they have been asked many times before.
>
> Sorry also if these questions are deemed silly such as a toddler might
ask.
"Out of the mouths of babes and sucklings…" [Psalms 8:2]
I congratulate Jane in presenting us with the heart of a precious FAQ list
which ought to figure prominently in Jwiki (…but doesn't *). Ditto
prominently displayed in Wikipedia (…but isn't). Brief but authoritative
answers to Jane's Seven Questions would not only dispel the fog of many
introductions to APL and J (…most of the many??), but cut straight to the
bone of both languages.
I personally can't do justice to Jane's questions without writing a book –
and it will be a most interesting book to write. And maybe to read. **
But both APL and J are notorious for their one-liners. I challenge the
community to furnish one-line answers to Jane's seven questions –J7Q
(you're allowed a modest-length comment). I have mine ready to-go, but I
want to see someone else's first.
Footnotes
(*) – searching Jwiki on "FAQ" gets you:
http://code.jsoftware.com/wiki/Guides/General_FAQ
http://code.jsoftware.com/wiki/Guides/Language_FAQ
…Both are stubs. It seems to me J's Frequently Asked Questions are not
Asked Anywhere Near Frequently Enough !:/!
(**) – Hats Off to Bob Bernecky for a superb impromptu paper on the
industrial archaeology of the APLs (Array-Processing Languages) One gets
the feeling he might have heard it all before :-)
On Thu, May 17, 2018 at 10:02 PM, Roger Hui <[email protected]>
wrote:
> I remember the paper well: The Prime Factorization of 1, by Jeffrey
> Shallit, now professor of mathematics at the University of Waterloo. n =
> */ q: n, therefore:
>
> */ q: 1
> 1
> q: 1
>
> (i.0) -: q: 1
> 1
>
>
>
> On Thu, May 17, 2018 at 1:56 PM, Nollaig MacKenzie <
> [email protected]> wrote:
>
> >
> > On 2018.05.17 13:14:26, you,
> > the extraordinary Roger Hui, spake thus:
> >
> > <...>
> > >
> > > One way to think about index origin, is to consider the question
> whether
> > 1
> > > is a prime. http://www.jsoftware.com/papers/APLDesignExercises1.htm#14
> > >
> >
> > Aeons ago, in _Quote Quad_, there was a paper, "The Prime Factors of 1".
> > Answer: i.0
> >
> >
> > --
> > Nollaig MacKenzie
> > ftp://ftp.nollaig.ca/pub/pap/
> > pgp key C6E9845A
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
> >
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>
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