retain removes all objects from the environment
except those mentioned as argument.
Usage
retain(..., list = character(0), envir = parent.frame(),force=FALSE)
Arguments
...
names of objects to be retained, as names (unquoted)
or character strings(quoted).
list
a character vector naming the objects to be retained.
envir
the environment from which the objects are removed
that are not to be retained.
force
logical value. As a measure of caution, this
function removes objects only from local environments,
unless force equals TRUE. In that case, retain can
also be used to clear the global environment, the user's workspace.
local({
foreach(x=c(a,b,c,d,e,f,g,h),x<-1)
cat("Objects before call to 'retain':\n")
print(ls())
retain(a)
cat("Objects after call to 'retain':\n")
print(ls())
})
x <- 1
y <- 2
retain(x)