R help - Sep 2011 - Variable scoping question

I modified an example in the object.size help page to create a function
I want to be able to run:

"mysize" <- function() {
    z <- sapply(ls(), function(w) object.size(get(w)))
    as.matrix(rev(sort(z))[1:5])
}
mysize()

When I test the lines inside the function it works fine:
>     z <- sapply(ls(), function(w) object.size(get(w)))
>     as.matrix(rev(sort(z))[1:5])
             [,1]
mat     166344288
mod     130794704
zidx       799664
wfidx      799664
megacap    799664
>
But when I try to run the function, it produces an error:
> "mysize" <- function() {
+     z <- sapply(ls(), function(w) object.size(get(w)))
+     as.matrix(rev(sort(z))[1:5])
+ }
> mysize()
Error in rev(sort(z)) : 
  error in evaluating the argument 'x' in selecting a method for
function 'rev': Error in sort.int(x, na.last = na.last, decreasing
decreasing, ...) :
  'x' must be atomic
> 
It must be a variable scoping problem, but I am not sure how to tackle
it.

Thanks,

Roger
***************************************************************

This message is for the named person's use only. It may\...{{dropped:14}}

On Sep 8, 2011, at 9:13 AM, Bos, Roger wrote:
> I modified an example in the object.size help page to create a  
> function
> I want to be able to run:
>
> "mysize" <- function() {
>    z <- sapply(ls(), function(w) object.size(get(w)))
>    as.matrix(rev(sort(z))[1:5])
> }
> mysize()
>
> When I test the lines inside the function it works fine:
>
>>    z <- sapply(ls(), function(w) object.size(get(w)))
>
>>    as.matrix(rev(sort(z))[1:5])
>             [,1]
> mat     166344288
> mod     130794704
> zidx       799664
> wfidx      799664
> megacap    799664
>>
>
> But when I try to run the function, it produces an error:
>
>> "mysize" <- function() {
> +     z <- sapply(ls(), function(w) object.size(get(w)))
> +     as.matrix(rev(sort(z))[1:5])
> + }
>
>> mysize()
> Error in rev(sort(z)) :
>  error in evaluating the argument 'x' in selecting a method for
> function 'rev': Error in sort.int(x, na.last = na.last, decreasing
> decreasing, ...) :
>  'x' must be atomic
>>
>
> It must be a variable scoping problem, but I am not sure how to tackle
> it.
I would have called it a function scoping problem. Inside the function  
ls() will not "see" the global environment unless you tell it where to
look. (It may even be two levels deeper than the globalenv() when  
called inside `sapply`.) When called without an environment, it just  
looks in parent.frame which is inside the function.

"mysize" <- function() {
      z <- sapply(ls(env=globalenv()), function(w) object.size(get(w)))
      as.matrix(rev(sort(z))[1:5])
  }

#works for me.


--
David Winsemius, MD
West Hartford, CT

Here is a function I use to look at the sizes of objects:

my.ls <-
function (pos = 1, sorted = FALSE)
{
    .result <- sapply(ls(pos = pos, all.names = TRUE), function(..x)
object.size(eval(as.symbol(..x))))
    if (sorted) {
        .result <- rev(sort(.result))
    }
    .ls <- as.data.frame(rbind(as.matrix(.result), `**Total` = sum(.result)))
    names(.ls) <- "Size"
    .ls$Size <- formatC(.ls$Size, big.mark = ",", digits = 0,
        format = "f")
    .ls$Mode <- c(unlist(lapply(rownames(.ls)[-nrow(.ls)], function(x)
mode(eval(as.symbol(x))))),
        "-------")
    .ls
}



On Thu, Sep 8, 2011 at 9:13 AM, Bos, Roger <roger.bos at rothschild.com>
wrote:
> I modified an example in the object.size help page to create a function
> I want to be able to run:
>
> "mysize" <- function() {
> ? ?z <- sapply(ls(), function(w) object.size(get(w)))
> ? ?as.matrix(rev(sort(z))[1:5])
> }
> mysize()
>
> When I test the lines inside the function it works fine:
>
>> ? ? z <- sapply(ls(), function(w) object.size(get(w)))
>
>> ? ? as.matrix(rev(sort(z))[1:5])
> ? ? ? ? ? ? [,1]
> mat ? ? 166344288
> mod ? ? 130794704
> zidx ? ? ? 799664
> wfidx ? ? ?799664
> megacap ? ?799664
>>
>
> But when I try to run the function, it produces an error:
>
>> "mysize" <- function() {
> + ? ? z <- sapply(ls(), function(w) object.size(get(w)))
> + ? ? as.matrix(rev(sort(z))[1:5])
> + }
>
>> mysize()
> Error in rev(sort(z)) :
> ?error in evaluating the argument 'x' in selecting a method for
> function 'rev': Error in sort.int(x, na.last = na.last, decreasing
> decreasing, ...) :
> ?'x' must be atomic
>>
>
> It must be a variable scoping problem, but I am not sure how to tackle
> it.
>
> Thanks,
>
> Roger
> ***************************************************************
>
> This message is for the named person's use only. It
may\...{{dropped:14}}
>
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?