pass objects into "..." (dot dot dot)

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 "...")?

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

? ? ? ?[[alternative HTML version deleted]]

Thank you for that. Sorry, I don't know how to use that to solve the issue.
I need to pass a handful (an unknown length) of objects into "...". I see
how you can get the count of what is in "...", but I'm not seeing how
knowing the length in "..." will help me.

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
Of Steve Lianoglou
Sent: Tuesday, May 15, 2012 10:49 AM
To: Ben quant
Cc: r-help at r-project.org
Subject: Re: [R] pass objects into "..." (dot dot dot)

Hi,

On Tue, May 15, 2012 at 1:38 PM, Ben quant <ccquant at gmail.com> wrote:

Thank you for that. Sorry, I don't know how to use that to solve the issue.
I need to pass a handful (an unknown length) of objects into "...". I see
how you can get the count of what is in "...", but I'm not seeing how
knowing the length in "..." will help me.

Hmm ... ok, I see. The interval_intersection function signature
suggests that this should work:

myIntersection <- function(...) {
  do.call(interval_intersection, unname(list(...)))
}

Or you can just make a list of intervals and do the same do.call mojo, ie:

do.call(interval_intersection, my.interval.list)

yay/nay?

-steve


--
Steve Lianoglou
Graduate Student: Computational Systems Biology
?| Memorial Sloan-Kettering Cancer Center
?| Weill Medical College of Cornell University
Contact Info: http://cbio.mskcc.org/~lianos/contact