You evidence a good deal of confusion. V&R's S PROGRAMMING, in particular
Chapter 3 (especially section 3.5 on Computing on the Language) would be
helpful to you. See also their example on p. 46.
However in brief:
foo <- function (...) {
x <-3
list(...)
}
returns the evaluated ... arguments as a list. But note that in your call
below, foo(a,b,c), the (actual) arguments tha you give are **unnamed** and
so you would get:
foo(a,b,c)
[[1]]
[1] 1
[[2]]
[1] 2
[[3]]
[1] 3
If you wanted the list components named, you must name them:
foo(a=a,b=b,c=c)
$a
[1] 1
$b
[1] 2
$c
[1] 3
There are subtleties here that I overlooked(e.g. what happens if the
arguments are expressions with promises, as for lazy evaluation?) As I said,
V&R provide a fairly comprehensive and (to me) accessible overview of these
things. It can be complicated, for sure.
-- Bert Gunter
Genentech Nonclinical Statistics
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of whizvast
Sent: Friday, June 27, 2008 8:48 AM
To: r-help@r-project.org
Subject: [R] getting multiple argument names
hi, all-
i wrote a function that accept multiple arguments, but don't know how to
assign names automatically. run the following code:
foo <- function (...) {
x = list(...)
names(x) <- deparse(substitute(...))
x
}
a = 1; b = 2; c = 3
y <- foo( a, b, c)
names(y)
as you can see, only the first items are correctly named.
how do i correct this problem?
--
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