1. The FAQ entry advise you to use a list, instead of using assign() in a
loop. Have you considered that?
2. See ?get.
Andy
From: kewley at eden.rutgers.edu>
> I've looked in the online documentation for this, but have
> been unable to find an answer. I can name variables
> dynamically, but I cannot call them dynamically. Either a
> direct answer or a reference to an online resource that has
> the answer would be great.
>
> I'm trying to write a script that imports and compares
> results from various IR (information retrieval systems). Each
> imported file will contain results for multiple (50+)
> queries, each query can have 2000+ results.
>
> My immediate task is to import the files and assign the
> scores for each query to its own variable (e.g. File1-Query1,
> File1-Query2, etc)
>
> I've written code that reads in the data files and enters
> them as variables:
>
> res.paths <-file.path(choose.files("c:/res/*.*"))
> num.files<- NROW(res.paths)
> for (j in 1: num.files) {
> assign(paste("res",j, sep=""),
read.table(res.paths[j]))
> This gives me variables named res1, res2, etc, one for each
> file. So far so good.
>
> But the next line of code is designed to find out how many
> unique values are in the first column (i.e. number of
> queries) of the file I just
> imported:
>
> assign(paste("res.count",j, sep="_"),
NROW(unique(res[j]$V1)))
> }
>
> What I expected is a variable named e.g. res.count_1.
> However, I get an
> error:
> Error in unique(res[j]$V1) : object "res" not found
>
> How can I dynamically call res1, res2, etc? I've also tried
> using quotes and paste, but with no success.
>
> Any help is appreciated.
>
> Andrew Noyes
> SCILS
> Rutgers University
>
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