[R] pass objects into "..." (dot dot dot)

[R. Michael Weylandt]

Are you perhaps looking for the do.call() construction?

z = Intervals(c(1,10))
y = Intervals(c(5,10))
x = Intervals(c(4,6))

do.call("interval_intersection", list(x,y,z))

Michael

On Tue, May 15, 2012 at 12:46 PM, Ben quant <ccquant at gmail.com> wrote:
> Hello,
>
> Thanks in advance for any help!
>
> How do I pass an unknown number of objects into the "..." (dot dot dot)
> parameter? Put another way, is there some standard way to pass multiple
> objects into "..." to "fool" the function into thinking the objects are
> passed in separately/explicitly with common separation (like "x,y,z" when
> x, y and z are objects to be passed into "...")?
>
> Details:
>
> I'm working with this parameter list and function:
>
> interval_intersection(x, ..., check_valid = TRUE)
>
> To illustrate...
>
> This works and I get the expected interval:
>
> library('intervals')
> # create individual Intervals objects
> z = Intervals(c(1,10))
> y = Intervals(c(5,10))
> x = Intervals(c(4,6))
>> interval_intersection(x,y,z)
> Object of class Intervals
> 1 interval over R:
> [5, 6]
>
> ...but at run time I don't know how many Intervals objects I will have so I
> can't list them explicitly like this "x,y,z". So I build a matrix of
> Intervals (per the package manual) and the function doesn't work:
>
>> xyz = matrix(c(4,5,1,6,10,10),nrow=3)
>> xyz
>     [,1] [,2]
> [1,]    4    6
> [2,]    5   10
> [3,]    1   10
>> xyz_interval = Intervals(xyz)
>> interval_intersection(xyz_interval)
> Object of class Intervals
> 1 interval over R:
> [1, 10]
>
> ...[1,10] is unexpected/wrong because I want the intersection of the three
> intervals. So I conclude that I need to pass in the individual Intervals
> objects, but how do I do that if I don't know how many I have at run time?
> I tried putting them in a list, but that didn't work. I also tried using
> paste(    ,sep=',') and get().
>
> Is there some standard way to pass multiple objects into "..." to "fool"
> the function into thinking they are passed in separately/explicitly with
> common separation?
>
> Thanks!
> ben
>
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>
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