Displaying 20 results from an estimated 30000 matches similar to: "does subset.data.frame need to accept extra arguments?"
2019 Aug 07
1
NextMethod() and argument laziness
Hi all, I'd like to ask if the following behavior is a bug. To me it
certainly feels surprising, at the very least. In this example, I would
like to call NextMethod() from my `child` object, have `cols` be left
untouched, and then substitute(cols) in the parent method. It works when
you use a `parent` object (as expected), but I would have also expected to
get `mpg` back when calling it from
2024 Feb 18
1
Capturing Function Arguments
? Sat, 17 Feb 2024 11:15:43 -0700
"Reed A. Cartwright" <racartwright at gmail.com> ?????:
> I'm wrapping a function in R and I want to record all the arguments
> passed to it, including default values and missing values.
This is hard if not impossible to implement for the general case
because the default arguments are evaluated in the environment of the
function as it
2015 Jan 28
2
[Q] Get formal arguments of my implemented S4 method
I'm attempting to reflect the information for use with corresponding
fields in GUI (in a different package), to provide default values,
argname as key for UI label lookups, etc.
So I want something much more like the formals of the implementation:
{
"object",
"method": c("median", "vs", "tukey"),
2015 Jan 29
3
[Q] Get formal arguments of my implemented S4 method
On Jan 28, 2015, at 6:37 PM, Michael Lawrence <lawrence.michael at gene.com> wrote:
> At this point I would just due:
>
> formals(body(method)[[2L]])
>
> At some point we need to figure out what to do with this .local() confusion.
Agreed, definitely. The current hack is to avoid re-matching arguments on method dispatch, so a fix would need to be fairly deep in the
1998 Jan 03
1
R-beta: NextMethod(.Generic) bug
I'm a day-old R newbie (but a war-weary S veteran), with couple of
first-day questions:
In R 0.61, this code fails.
Ops.test <- function(e1,e2)
{
e1 <- NextMethod(.Generic)
e1
}
x <- 4
class(x) <- "test"
y <- x < 3
The error message is "Error in NextMethod(.Generic) : negative length vectors
are not allowed.".
I assume it is a bug.
2013 Jun 28
3
problem with eval(..., parent.frame(1L)) when package is not loaded
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
The lmer() function in the lme4 package has some code of the form
mc <- match.call()
mc[[1]] <- as.name("lFormula")
lmod <- eval(mc, parent.frame(1L))
this is a fairly common idiom in R, found e.g. in lm(), used when
one wants to pass all of the arguments of a function to a different
function (in the case of lm() it's
2009 May 19
4
Qs: The list of arguments, wrapping functions...
Hi. I'm pretty new to R, but I've been programming in other languages for
some time. I have a couple of questions regarding programming with function
objects.
1. Is there a way for a function to refer generically to all its actual
arguments as a list? I'm thinking of something like the @_ array in Perl or
the arguments variable in JavaScript. (By "actual" I mean the ones
2015 Jan 28
2
[Q] Get formal arguments of my implemented S4 method
Interrogating some (of my own) code in another package.
>norm.meth <- getMethod("normalize", "MatrixLike")
>message("str(norm.meth)")
>str(norm.meth)
>message("show(norm.meth at .Data)")
>show(norm.meth at .Data)
Last show() displays this:
function (object, ...)
{
.local <- function (object, method = c("median",
2011 May 26
1
Is it possible to define a function's arguments via a wildcard in 'substitute()'?
Dear List,
just out of pure curiosity: is it possible to define a function via
'substitute()' such that the function's formal arguments are specified
by a "wildcard" that is substituted when the expression is evaluated?
Simple example:
x.args <- formals("data.frame")
x.body <- expression(
out <- myArg + 100,
return(out)
)
expr <-
2011 Oct 22
2
Expanding rows of a data frame into multiple rows
The setup: I have a data frame where one column is in list mode, and
each entry contains a vector of varying length.
I want to expand this into a data frame with one row for each member
of the list-mode column (the other values being replicated)
For example, an example input and the desired output would be:
input <- data.frame(site = 1:6,
sector =
2009 Aug 08
2
Problem using model.frame with argument subset in own function
Dear List,
I am writing a formula method for a function in a package I maintain. I
want the method to return a data.frame that potentially only contains
some of the variables in 'data', as specified by the formula.
The problem I am having is in writing the function and wrapping it
around model.frame. Consider the following data frame:
dat <- data.frame(A = runif(10), B = runif(10), C
2018 Aug 13
2
substitute() on arguments in ellipsis ("dot dot dot")?
Interestingly,
as.list(substitute(...()))
also works.
On Sun, Aug 12, 2018 at 1:16 PM, Duncan Murdoch
<murdoch.duncan at gmail.com> wrote:
> On 12/08/2018 4:00 PM, Henrik Bengtsson wrote:
>>
>> Hi. For any number of *known* arguments, we can do:
>>
>> one <- function(a) list(a = substitute(a))
>> two <- function(a, b) list(a = substitute(a), b =
2014 Nov 28
1
Feature request: mixing `...` (three dots) with other formal arguments in S4 methods
Well, the benefit lies in the ability to pass along arguments via `...` to
more than one recipient that use *identical argument names* and/or when
these recipients are not necessarily located on the same calling stack
layer.
I'm *not* after a *general* change in the way arguments are
dispatched/functions are called as I'm actually a big friend of keepings
things quite explicit (thus
2015 Jan 29
1
[Q] Get formal arguments of my implemented S4 method
Would we really need the special class or would simply checking the formals
of the method against those of the generic be simple and fast enough?
On Thu, Jan 29, 2015 at 9:41 AM, John Chambers <jmc at r-project.org> wrote:
> I wouldn't want to add more to the current approach; if someone would like
> to devote some time, the much preferable idea IMO would be to replace the
>
2015 Jan 29
2
[Q] Get formal arguments of my implemented S4 method
I wish it didn't have to depend on the name '.local'.
Back when I wrote a lot of S4 methods I avoided the auto-generated .local
and named the local function something that made sense so that is was easier
for a user to track down the source of an error.
E.g., define the generic QQQ with numeric and integer methods:
setGeneric("QQQ",
function(x, ...)NULL)
2012 Apr 05
2
indexing data.frame columns
Consider the data.frame:
df <- data.frame(A = c(1,4,2,6,7,3,6), B= c(3,7,2,7,3,5,4), C =
c(2,7,5,2,7,4,5), index = c("A","B","A","C","B","B","C"))
I want to select the column specified in 'index' for every row of 'df', to
get
goal <- c(1, 7, 2, 2, 3, 5, 5)
This sounds a lot like the indexing-by-a-matrix
2024 Feb 17
2
Capturing Function Arguments
I'm wrapping a function in R and I want to record all the arguments
passed to it, including default values and missing values. I want to
be able to snoop on function calls in sourced scripts as part of a
unit testing framework.
I can capture the values fine, but I'm having trouble evaluating them
as if `force()` had been applied to each of them.
Here is a minimal example:
f0 <-
2005 Feb 17
4
Getting *types* of arguments?
Hello world,
short question: is there a possibility to get a list of
arguments of a function *with* variable/parameter types?
formals() gives me the names of the parameters, but says
nothing about the parameter type it expects (I know I can always use the
help function).
I would like somthing like
$x: vector or data.frame...
Thanks in advance...
Georg
--
Georg Hoermann, Fachabteilung
2014 Jan 19
1
formals() adds 0 to complex function arguments
Dear list,
I'm facing an issue with the automated documentation of a function using
roxygen2. The function has a complex-valued default argument, which is
picked up by roxygen2 using formals() to generate the corresponding Usage
section of the Rd file. Unfortunately, it appears that formals() reformats
complex numbers. Consider the example below,
test <- function(a = 1+2i){}
>
2012 Oct 04
2
How to build a list with missing values? What is missing, anyway?
This is tangentially related to Hadley's question.
Suppose I'm building a function programmatically; I have assembled an
expression for the body and I know the names of the arguments it wants
to take.
Suppose I have some convenience function such that writing
make_function(alist(a=, b=), quote(a+b), environment())
is equivalent to writing
function(a,b) a+b
So how do I make the