R help - Jan 2010 - Data frame of different sized lists in a function call

I'm hoping to get some "best practice" feedback for constructing a
function call which takes an undefined set of DIFFERENT length vectors 
-- e.g. say we have two lists:

list1=c(1:10)
list2=c(2:4)

lists = data.frame(list1,list2) coerces those two to be the same length 
(recycling list2 to fill in the missing rows) -- what is a quick way of 
having each of those lists retain their original lengths?  my function 
ultimately should look like:


myfunction = function(lists) {

...

}

I'm hoping this can be done with a single line, so the user doesn't have
to pre-construct the data.frame before running the function, if at all 
possible.

Thanks!

--j

-- 

Jonathan A. Greenberg, PhD
Postdoctoral Scholar
Center for Spatial Technologies and Remote Sensing (CSTARS)
University of California, Davis
One Shields Avenue
The Barn, Room 250N
Davis, CA 95616
Phone: 415-763-5476
AIM: jgrn307, MSN: jgrn307 at hotmail.com, Gchat: jgrn307

On Jan 28, 2010, at 4:03 PM, Jonathan Greenberg wrote:
> list1=c(1:10)  # neither of which really are lists
> list2=c(2:4)
>
> lists = list(list1,list2)  $ a list of two vectors.
David Winsemius, MD
Heritage Laboratories
West Hartford, CT

If you understand the differences between R lists and R vectors then this should
be easy:
> vec1 <- 1:10
> vec2 <- 2:4
> myListOfVectors <- list( vec1, vec2 )
Now you can pass the single list of 2 different sized vectors to your function. 
For more details on working with lists (and vectors and functions and ... ) read
"An Introduction to R" which is worth a lot more than you pay for it.

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Jonathan Greenberg
> Sent: Thursday, January 28, 2010 2:03 PM
> To: r-help
> Subject: [R] Data frame of different sized lists in a function call
> 
> I'm hoping to get some "best practice" feedback for
constructing a
> function call which takes an undefined set of DIFFERENT length vectors
> -- e.g. say we have two lists:
> 
> list1=c(1:10)
> list2=c(2:4)
> 
> lists = data.frame(list1,list2) coerces those two to be the same length
> (recycling list2 to fill in the missing rows) -- what is a quick way of
> having each of those lists retain their original lengths?  my function
> ultimately should look like:
> 
> 
> myfunction = function(lists) {
> 
> ...
> 
> }
> 
> I'm hoping this can be done with a single line, so the user doesn't
> have
> to pre-construct the data.frame before running the function, if at all
> possible.
> 
> Thanks!
> 
> --j
> 
> --
> 
> Jonathan A. Greenberg, PhD
> Postdoctoral Scholar
> Center for Spatial Technologies and Remote Sensing (CSTARS)
> University of California, Davis
> One Shields Avenue
> The Barn, Room 250N
> Davis, CA 95616
> Phone: 415-763-5476
> AIM: jgrn307, MSN: jgrn307 at hotmail.com, Gchat: jgrn307
> 
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