loading saved files with objects in same names
On 20/08/2014, 8:58 AM, Barry Rowlingson wrote:
On Tue, Aug 19, 2014 at 1:30 AM, Jinsong Zhao <jszhao at yeah.net> wrote:
Hi there, I have several saved data files (e.g., A.RData, B.RData and C.RData). In each file, there are some objects with same names but different contents. Now, I need to compare those objects through plotting. However, I can't find a way to load them into a workspace. The only thing I can do is to rename them and then save and load again. Is there a convenient to load those objects? Thanks a lot in advance.
The technique of loading into an environment already mentioned can be cleaned up and put into a function. First lets save a thing called "x" into two files with different values:
> x="first" > save(x,file="f.RData")) > x="second" > save(x,file="s.RData")
This little function wraps the loading:
> getFrom=function(file, name){e=new.env();load(file,env=e);e[[name]]}
So now I can get 'x' from the first file - the value is returned from `getFrom` so I can assign it to anything:
> x1 = getFrom("f.RData","x")
> x1
[1] "first"
> x2 = getFrom("s.RData","x")
> x2
[1] "second" And I can even loop over RData files and read in all the `x`s into a vector:
> sapply(c("f.RData","s.RData"),function(f){getFrom(f,"x")})
f.RData s.RData "first" "second" (on second thoughts, possibly 'loadFrom' is a better name)
That's a nice little function. You could also have lsFrom, that lists
the objects stored in the file, along the same lines:
lsFrom <- function(file, all.names = FALSE, pattern) {
e <- new.env()
load(file, envir = e)
ls(e, all.names = all.names, pattern = pattern)
}
Duncan Murdoch