[Rd] Re: [R] Is k equivalent to k:k ?
Richard A. O'Keefe
ok at cs.otago.ac.nz
Sun Dec 12 22:56:48 CET 2004
I asked:
> In this discussion of seq(), can anyone explain to
> me _why_ seq(to=n) and seq(length=3) have different
> types?
Martin Maechler <maechler at stat.math.ethz.ch> replied:
well, the explantion isn't hard: look at seq.default :-)
That's the "efficient cause", I was after the "final cause".
That is, I wasn't asking "what is it about the system which MAKES this
happen" but "why does anyone WANT this to happen"?
now if that really makes your *life* simpler, what does that
tell us about your life ;-) :-)
It tells you I am revising someone else's e-book about S to describe R.
The cleaner R is, the easier that part of my life gets.
In the future, we really might want to have a new type,
some "long integer" or "index" which would be used both in R
and C's R-API for indexing into large objects where 32-bit
integers overflow.
It would be useful needed now for large file support and for Java interfacing.
I assume, we will keep the R "integer" == C "int" == 32-bit int
forever, but need something with more bits rather sooner than later.
But in any, case by then, some things might have to change in
R (and C's R-API) storage type of indexing.
seq: from, to, by, length[.out], along[.with]
I'm about to fix this (documentation, not code).
Please don't. There's a lot of text out there: tutorials, textbooks,
S on-inline documentation, &c which states over and over again that
the arguments are 'along' and 'with'. Change the documentation, and
people will start writing length.out, and will that port to S-Plus?
(Serious question: I don't know.)
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