R help - Apr 2011 - passing a vector of variable names to the ... pairlist function argument

Hi,

I have a character vector that contains the names of several objects  
that I would like to pass to a function (specifically, the ridge  
function in the survival package, but cbind is a similar example).   
I've been struggling with how to do this so that the object values get  
interpreted by the function, rather than the object names.

For example,
x1 <- 1:4
x2 <- 2:5
x3 <- 3:6
xs <- c("x1", "x2", "x3")

If I wanted to cbind(x1, x2, x3) without typing this out, how would I  
do it?

Thanks very much!

Jessica Myers
Instructor in Medicine
Division of Pharmacoepidemiology
Brigham and Women's Hospital



The information in this e-mail is intended only for the ...{{dropped:7}}

On 21.04.2011 16:03, Jessica Myers wrote:
> Hi,
>
> I have a character vector that contains the names of several objects
> that I would like to pass to a function (specifically, the ridge
> function in the survival package, but cbind is a similar example). I've
> been struggling with how to do this so that the object values get
> interpreted by the function, rather than the object names.
>
> For example,
> x1 <- 1:4
> x2 <- 2:5
> x3 <- 3:6
> xs <- c("x1", "x2", "x3")
>
> If I wanted to cbind(x1, x2, x3) without typing this out, how would I do
> it?

For the cbind case, I'd omit cbind and ask R to:

   sapply(xs, get)

or

   apply(matrix(xs), 1, get)

or with cbind():

   do.call("cbind", lapply(xs, get))

the latter can be generalized for other function calls, of course.

Best,
Uwe Ligges



> Thanks very much!
>
> Jessica Myers
> Instructor in Medicine
> Division of Pharmacoepidemiology
> Brigham and Women's Hospital
>
>
>
> The information in this e-mail is intended only for the ...{{dropped:7}}
>
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