R help - Feb 2011 - Return list of data frames.

Hi,

I've got a problem with a function trying to return 2 data frames in a list.
The code is as follow:

function(x) {

# code....

MyList<- list("a"=df.a,"b"=df.b)
return(MyList)

}

and I got the following message:

Error in list_to_dataframe(res, attr(.data, "split_labels")) :
  Results must be all atomic, or all data frames

At first instance I thought it may be down that both df have same variable
names so I changed var names in df.a - but I am still getting the same error
then I changed my lIst to  MyList<- list(df.a,df.b)  just to try something
different and still getting the same issue.

Now I wondering if the error is down to the difference in size for each data
frame df.a (r=500,c=8) and df.b(r=1,c=4) - if this is the case then I don'
know how to fix it.

Any ideas?

Sorry, I've got one more question, once I return the list from my function
how can I split out my list to get the original 2 data frames or how can I
access each one independently, i.e. assign them to a data frame again.. if
that makes sense.

I am using 2.12.1 on Win7

Regards,

Alberto

	[[alternative HTML version deleted]]

Hi Alberto,
I don't think the error is coming from the code you've shown us
(although quoting the list names is a little strange).

This works for me:

f <- function() {
    df.a <- data.frame(x=sample(letters, 100, replace=TRUE), y=rnorm(100))
    df.b <- data.frame(z=factor(letters), y = factor(1:26))
MyList<- list("a"=df.a, "b"=df.b)
return(MyList)
}

f()

Please follow the posting guide, and include a short reproducible example.

Best,
Ista

On Mon, Feb 14, 2011 at 11:57 AM, Alberto Negron
<albertonegron at gmail.com> wrote:
> Hi,
>
> I've got a problem with a function trying to return 2 data frames in a
list.
> The code is as follow:
>
> function(x) {
>
> # code....
>
> MyList<- list("a"=df.a,"b"=df.b)
> return(MyList)
>
> }
>
> and I got the following message:
>
> Error in list_to_dataframe(res, attr(.data, "split_labels")) :
> ?Results must be all atomic, or all data frames
>
> At first instance I thought it may be down that both df have same variable
> names so I changed var names in df.a - but I am still getting the same
error
> then I changed my lIst to ?MyList<- list(df.a,df.b) ?just to try
something
> different and still getting the same issue.
>
> Now I wondering if the error is down to the difference in size for each
data
> frame df.a (r=500,c=8) and df.b(r=1,c=4) - if this is the case then I
don'
> know how to fix it.
>
> Any ideas?
>
> Sorry, I've got one more question, once I return the list from my
function
> how can I split out my list to get the original 2 data frames or how can I
> access each one independently, i.e. assign them to a data frame again.. if
> that makes sense.
>
> I am using 2.12.1 on Win7
>
> Regards,
>
> Alberto
>
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org