Using the get() function on an object within a list
On Mar 30, 2010, at 5:23 PM, klc wrote:
Hi-
I am trying use the get function to return the value of an object
within a
list. As an abbreviated example:
"original" represents a list of several objects, one of which is "a.
1".
original<-vector('list',5)
names(original) <- c("a.1","a.2","a.3","b.1","b.2")
original$a.1 <- c(4,3)
When I enter:
original$a.1
R returns the following vector
[1] 4 3
however, when I enter:
get("original$a.1")
> get("original")$a.1
[1] 4 3
The get function will not parse and evaluate complex expressions for
you. And the "$" operator is probably not as useful for this
application as "[[" would be. See below
R returns the following error:
"Error in get("original$a.1") : object 'original$a.1' not found"
Does anyone happen to know how to resolve this error?
I pose this question because ultimately I would like to use the get
function
to convert particular objects within "original" into separate lists
as:
species <- c(1,2,3)
A <- vector('list',length(species))
A <- lapply(paste("original$a.", species, sep=""), get)
> sapply(names(original), function(x) original[[x]]) $a.1 [1] 4 3 $a.2 NULL $a.3 NULL $b.1 NULL $b.2 NULL > sapply(1:3, function(x) original[[x]]) [[1]] [1] 4 3 [[2]] NULL [[3]] NULL
I apologize if I missed this question in a previous post. Many thanks- -- View this message in context: http://n4.nabble.com/Using-the-get-function-on-an-object-within-a-list-tp1745965p1745965.html Sent from the R help mailing list archive at Nabble.com.
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD West Hartford, CT