[R] Loop over rda list files and using the attach function

Greg Snow 538280 at gmail.com
Tue Aug 30 20:36:43 CEST 2016

You can attach rda files directly with the attach function, no need to
load them first (see the what argument in the help for attach).  This
may do what you want more directly.

In general it is better to not use loops and attach for this kind of
thing.  It is better to store multiple data objects in a list, then
use lapply/sapply to apply functions to each element.

On Tue, Aug 30, 2016 at 9:43 AM, Juan Ceccarelli Arias
<jfca283 at gmail.com> wrote:
> Hi.
> I need to loop over rda files.
> I generated the list of them.
> That's ok. The problem is that the name of the files are as yyyy_mm (eg
> 2010_01 is january or 2010, 2016_03 is march of 2016).
> So, when i try to use the attach function to create a simple table(age,
> sex) it fails.
> The only way to attach a file as is using
> attach(`2016_03`)
> The text above i have no idea how to declare it in my code below
> dd=list.files("C:/Users/Me/r", pattern="rda$", full.names=F)
> for (i in 1:length(dd)) {
> yyz=load(dd[i])
> attach(yyz)
> table(age, sex)
> rm(list=yyz)
> }
> This is the error it declares the loop:
> Error in attach(yyz) : file '2013_02' not found
> Thanks for your help and time
>         [[alternative HTML version deleted]]
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Gregory (Greg) L. Snow Ph.D.
538280 at gmail.com

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