Ben Bolker [EMAIL PROTECTED] wrote:
Yes, although this becomes tedious if (e.g.) you have a function that
calls two different functions, each of which has many arguments (e.g.
plot() and barplot(); then you have to set up a whole lot of arguments
that default
On Wed, 17 Sep 2003, Simon Fear wrote:
There have been various elegant solutions to test for the presence
of a particular named parameter within a ... argument, such as
if (!is.null(list(...)$ylim))
if (ylim %in% names(list(...)))
I think I'd have to comment these lines pretty clearly if
Thanks for the insight.
-Original Message-
From: Prof Brian Ripley [mailto:[EMAIL PROTECTED]
snip
dots - list(...)
haveYlim - ylim %in% names(dots)
is the sort of thing we still understand 5 years later.
I didn't say understand, I said easily follow. Obviously how
easily is
At Wednesday 11:19 AM 9/17/2003 +0100, Simon Fear wrote:
There have been various elegant solutions to test for the presence
of a particular named parameter within a ... argument, such as
if (!is.null(list(...)$ylim))
if (ylim %in% names(list(...)))
I think I'd have to comment these lines pretty
Tony, I don't understand what you mean. Could you give
an example?
-Original Message-
From: Tony Plate [mailto:[EMAIL PROTECTED]
... I'm not saying never write functions that use ...,
I'm just saying never write functions that depend on a particular
argument being passed via
Simon, I agree, for some (maybe most) arguments it is good to know what
defaults are being used. But there are some for which I really don't want
to know. An example of the latter is arguments that control interaction
with a database. Suppose I have a low-level interaction function that
On Tue, 16 Sep 2003 [EMAIL PROTECTED] wrote:
Dear R users,
I want to retrieve ... argument values within a function. Here is a small
exmaple:
myfunc - function(x, ...)
{
if (hasArg(ylim)) a - ylim
plot(x, ...)
}
One solution is
dots-substitute(list(...))
For most purposes a more useful technique is to write the
function with a default NULL argument
myfunc - function(x, ylim=NULL)
so that it can be called as myfunc(x) or myfunc(x,y). Inside
the function you test for !is.null(ylim) and take appropriate
action.
Alternatively, and maybe more
[EMAIL PROTECTED] writes:
Dear R users,
I want to retrieve ... argument values within a function. Here is a small
exmaple:
myfunc - function(x, ...)
{
if (hasArg(ylim)) a - ylim
plot(x, ...)
}
x - rnorm(100)
myfunc(x, ylim=c(-0.5, 0.5))
Error in myfunc(x, ylim =
Huan -
Look at the function code for order(). To show the function
definition, type just order at the command line (no quotes,
no parentheses). This example is what I found most useful
when I had a similar question. The green book is also useful.
- tom blackwell - u michigan medical
Try:
myfunc - function(x, ...)
{
if (hasArg(ylim)) a - ...$ylim
plot(x, ...)
}
HTH,
Andy
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Tuesday, September 16, 2003 10:14 AM
To: [EMAIL PROTECTED]
Subject: [R] Retrieve ... argument
.
-Original Message-
From: Ben Bolker [mailto:[EMAIL PROTECTED]
Sent: 16 September 2003 16:18
To: Simon Fear
Cc: [EMAIL PROTECTED]; R help list
Subject: RE: [R] Retrieve ... argument values
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Andy on x234
Yes, although this becomes tedious if (e.g.) you have a function that
calls two different functions, each of which has many arguments (e.g.
plot() and barplot(); then you have to set up a whole lot of arguments
that default to NULL and, more annoyingly, you have to document them all
in
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