file path

Thanks for the suggestion. The file name in my case is Chinese, which
makes the regular expression less useful.

Anyway, I would like to pose a followup question.
I have a character string of "ABC\D", and want to strip away the "\"
and want a returned character of "ABCD". How can I do it with gsub() ?

Thanks again.

On 9 May 2012 22:40, Duncan Murdoch <murdoch.duncan at gmail.com> wrote:

On 09/05/2012 4:03 AM, Wincent wrote:

Dear all, is there any function to assert whether a file path is
legitimate, and to convert any potential file path to a legitimate
file path?

I automate a batch of files and write them to plain text files with
cat(). The file argument of cat() is generated automatically which may
contain characters such as ?<  >, unacceptable in Windows OS. What I
do at this moment is to strip such characters off with gsub(). Is
there any direct way to make legitimate file path without detailed
knowledge about the naming rule specific to a OS?

I would just try to create the file, and if you fail, it's not legitimate.
 Alternatively, you could look at the tests that R uses when it checks a
package:  we try to keep filenames portable to all operating systems.  The
rules seem to be strictest for vignettes:

       ## we specify ASCII filenames starting with a letter in R-exts
       ## do this in a locale-independent way.
       OK <-
grep("^[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz][ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789._-]+$",
vignettes)

Duncan Murdoch

-- 
Wincent Ronggui HUANG
Sociology Department of Fudan University
PhD of City University of Hong Kong
http://homepage.fudan.edu.cn/rghuang/cv/