[R] Zero Index Origin?
Gabor Grothendieck
ggrothendieck at myway.com
Wed Mar 31 15:19:38 CEST 2004
If you are willing to do it yourself you can define a class
for which indexing behaves that way.
For example, here is a start for a limited implementation for
vectors. The first statement defines the constructor, the
second defines [, the third converts an index 0 based vector
back to a regular vector, the next implements lvalues and
the last provides print method.
as.vector0 <- function(x) structure(x, class="vector0")
"[.vector0" <- function(x,i) as.vector0(as.vector.vector0(x)[i+1])
as.vector.vector0 <- function(x) unclass(x)
"[<-.vector0" <- function(x,i,value) {
x <- as.vector.vector0(x)
x[i+1] <- value
as.vector0(x)
}
print.vector0 <- function(x) print(as.vector.vector0(x))
# Test:
x <- as.vector0(1:10)
x[0:4] <- 100 * x[0:4]
x
Bob Cain <arcane <at> arcanemethods.com> writes:
:
: I'm very new to R and utterly blown away by not only the
: language but the unbelievable set of packages and the
: documentation and the documentation standards and...
:
: I was an early APL user and never lost my love for it and in
: R I find most of the essential things I loved about APL
: except for one thing. At this early stage of my learning I
: can't yet determine if there is a way to effect what in APL
: was zero index origin, the ordinality of indexes starts with
: 0 instead of 1. Is it possible to effect that in R without
: a lot of difficulty?
:
: I come here today from the world of DSP research and
: development where Matlab has a near hegemony. I see no
: reason whatsoever that R couldn't replace it with a _far_
: better and _far_ less idiosyncratic framework. I'd be
: interested in working on a Matlab equivalent DSP package for
: R (if that isn't being done by someone) and one of the
: things most criticized about Matlab from the standpoint of
: the DSP programmer is its insistence on 1 origin indexing.
: Any feedback greatly appreciated.
:
: Thanks,
:
: Bob
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