Another option is to use a closure, which isolates the arguments explicitly.
aFunction <- function(data, alpha, ...)
{
transform(alpha, ...)
rowMeans(data) > alpha
}
f <- function(data, selection, ...)
{
selected <- selection(data) # Remove ellipsis from here
plot(data[selected, ], ...)
}
f(aDataset, function(data) aFunction(data, alpha = 10, transform = sqrt), pch =
19)
Brian Lee Yung Rowe
Founder, Zato Novo
Professor, M.S. Data Analytics, CUNY
On May 28, 2014, at 7:34 AM, Duncan Murdoch <[email protected]> wrote:
> On 28/05/2014, 2:00 AM, Dario Strbenac wrote:
>> Hello
>>
>> If I have a function
>>
>> aFunction <- function(data, alpha, ...)
>> {
>> transform(alpha, ...)
>> rowMeans(data) > alpha
>> }
>>
>> f <- function(data, selection, ...)
>> {
>> selected <- selection(data, ...)
>> plot(data[selected, ], ...)
>> }
>>
>> f(aDataset, aFunction, alpha = 10, pch = 19, transform = sqrt)
>>
>> and selection calls another function, which has ... and that function calls
>> other functions, is there an easier way than getting the formals of all the
>> functions called internally by selection, and all of the formals of
>> functions called by plot ? Is there any option to change the error into a
>> warning message ?
>
> You can use try() to catch an error, but you can't ignore it. The code that
> triggered the error will still exit at that point.
>
> There are at least two common ways of handling the situation where you want
> to pass optional args to two different functions. One is to use
>
> args <- list(...)
>
> to get all the arguments in a list, and then manually split up the list, and
> use do.call() to pass some of them on. Generally you would do this only if
> you knew in advance how to split the args, you wouldn't try to call formals()
> to work it out at run-time.
>
> Another way is to have an argument like "control" in optim(), and ask the
> user to pass one set of options via that, and the other via ... . You'd use
> do.call() again to construct that call.
>
> Duncan Murdoch
>
> ______________________________________________
> [email protected] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
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