On 11/07/2010 1:30 PM, Prof Brian Ripley wrote:
On Sun, 11 Jul 2010, Tony Plate wrote:
Another way of seeing the environments referenced in an object is using
str(), e.g.:
f1 <- function() {
+ junk <- rnorm(10000000)
+ x <- 1:3
+ y <- rnorm(3)
+ lm(y ~ x)
+ }
v1 <- f1()
object.size(f1)
1636 bytes
grep("Environment", capture.output(str(v1)), value=TRUE)
[1] " .. ..- attr(*, \".Environment\")=<environment: 0x01f11a30> "
[2] " .. .. ..- attr(*, \".Environment\")=<environment: 0x01f11a30> "
'Some of the environments in a few cases': remember environments have
environments (and so on), and that namespaces and packages are also
environments. So we need to know about the environment of
environment(v1$terms), which also gets saved (either as a reference or
as an environment, depending on what it is).
And this approach does not work for many of the commonest cases:
f <- function() {
+ x <- pi
+ g <- function() print(x)
+ return(g)
+ }
g <- f()
str(g)
function ()
- attr(*, "source")= chr "function() print(x)"
ls(environment(g))
[1] "g" "x"
In fact I think it works only for formulae.
-- Tony Plate
On 7/10/2010 10:10 PM, bill.venab...@csiro.au wrote:
Well, I have answered one of my questions below. The hidden
environment is attached to the 'terms' component of v1.
Well, not really hidden. A terms component is a formula (see
?terms.object), and a formula has an environment just as a closure
does. In neither case does the print() method tell you about it --
but ?formula does.
I've just changed the default print method for formulas to display the
environment if it is not globalenv(), which is the rule used for
closures as well. So now in R-devel:
> as.formula("y ~ x")
y ~ x
as before, but
> as.formula("y ~ x", env=new.env())
y ~ x
<environment: 01f83400>
Duncan Murdoch
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