[R] parent in Creating environment object

[Duncan Murdoch]

On 8/1/2008 9:46 AM, Benjamin Otto wrote:
> Hi,
> 
> I would like to convert a simple list into an environment object. It seems I
> have to create an environment object with new.env() and assign the single
> values afterwards. Now what I did not really understand from the guides
> until now is, how the parent environment supplied to the new.env() function
> influence the final environment. So:

Environments aren't just lists of objects, they also specify where to 
look if a particular entry is not found, i.e. they say to look in the 
parent.
> 
> 1. Do I ALWAYS have to supply a parent during creation?

No, you'll get a default one, which is the current evaluation 
environment.  For example,

 > f <- function() {
+    x <- 123
+    return(new.env())
+ }
 >
 > e <- f()
 > e$x
NULL

Using the $ notation does *not* look in the parent.

 > get("x", e)
[1] 123

Using get() does, unless

 > get("x", e, inherits=FALSE)
Error in get("x", e, inherits = FALSE) : variable "x" was not found

you say "inherits=FALSE".

Duncan Murdoch


> 2. If yes, what would that be, when all I want is a conversion from a simple
> list?
> 
> Best regards
> 
> Benjamin
> 
> ======================================
> Benjamin Otto
> University Hospital Hamburg-Eppendorf
> Institute For Clinical Chemistry
> Martinistr. 52
> D-20246 Hamburg
> 
> Tel.: +49 40 42803 1908
> Fax.: +49 40 42803 4971
> ======================================
> 
> 
> 
> 
> 
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