Dear kxk,
Here are a couple of options:

# Option 1 -- sapply
mydata <- sapply(1970:2005, function(i){
                      mydata <- read.table(file = paste("edge_", i, ".csv",
sep=""), header=TRUE)
                     # more code goes here
                    }
                  )

Please note that mydata would be a list, so to access the data for 1970,
type mydata[[1]] in the R Console.

# Option 2  -- create a function foo
Another possibility would be to create a function, e.g foo, that reads the
data in and does the procedures you need for each file. It would be
something like:

foo <- function(nameFile){
          mydata <- read.table(file = paste("edge_", nameFile, ".csv",
sep=""), header=T)
         # more code goes here
             }

To do what you want for one file, just type

onefile <- foo(1970)

in the R Console. To do all your files at once, then

myresults <- sapply(1970:2005, foo)

is what you need. Once again, myresults would be a list.

Now, If you insist using a for loop, then

1. Avoid to use "t". It is an R function. See ?t
2. Rewrite your loop as

edge <- NULL
for (i in 1970:2005){
          edge[[i]] <- read.table(file = paste("edge_", i, ".csv", sep=""),
header=TRUE)
         # more code goes here
           }

3. Use the "[[" operator to extract the information you need from "edge".

Also, you might be interested in the foreach package <
http://cran.r-project.org/web/packages/foreach/>. Take a look at the
Vignette that come with it.

See ?sapply and ?"for" for more details.

HTH,

Jorge



On Wed, Jul 22, 2009 at 5:46 PM, kxk <kkong@u.washington.edu> wrote:

>
> I want to use read.table to input many files, each for a different year.  I
> would like to use the macro variable 't' to refer to the exact file that I
> would like to input the data using read.table.  How could I do this?  Thank
> you!
>
> for (t in 1970:2005)
> { edge <- read.table(file="edge_t.csv", header=T,  sep=",")
> ## I will  have many rows of code following the read.table line
> }
>
> --
> View this message in context:
> http://www.nabble.com/How-to-use-macro-variable-in-a-text-string-tp24615030p24615030.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help@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.
>

	[[alternative HTML version deleted]]


