Running R Script on a Sequence of Files

"This is almost a macro problem. It could be done in SAS language using
the WPS product (660 USD) I think. ..." 

OUCH! Why do it the complicated way??? Check out ?dir, ?list.files, and
then ?lapply for a simple start.

Don't give up so soon! When it comes to R there is no need to punt - you
can always keep possession of the ball ... :-)

Cheers,
Jagat

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Ajay ohri
Sent: Friday, December 05, 2008 12:59 PM
To: Chris Poliquin
Cc: r-help at r-project.org
Subject: Re: [R] Running R Script on a Sequence of Files

This is almost a macro problem. It could be done in SAS language using
the
WPS product (660 USD) I think.
It is a familiar problem and I would be quite interested in the result.

Is there any concept of Macros in R or a package to do the same.

Regards,

Ajay

On Fri, Dec 5, 2008 at 11:31 PM, Chris Poliquin

Hi,

I have about 900 files that I need to run the same R script on.  I

looked

over the R Data Import/Export Manual and  couldn't come up with a way

to

read in a sequence of files.

The files all have unique names and are in the same directory.  What I

want

to do is:
1) Create a list of the file names in the directory (this is really

what I

need help with)
2) For each item in the list...
       a) open the file with read.table
       b) perform some analysis
       c) append some results to an array or save them to another file
3) Next File

My initial instinct is to use Python to rename all the files with

numbers

1:900 and then read them all, but the file names contain some

information

that I would like to keep intact and having to keep a separate

database of

original names and numbers seems inefficient.  Is there a way to have

R read

all the files in a directory one at a time?

- Chris

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