R help - Oct 2008 - regexpr syntax question

Greetings R list,
 
I am stuck on a simple syntax problem. I want to list all files in a directory,
excluding files of a certain type. I have tried pattern matching as follows:
 
 
a <- list.files(data, full.name = TRUE, pattern != ".xml")  #
exclude all .xml files
 
 
The warning returns that my syntax is incorrect. I have read the regexpr help
files and search old posts to no avail. I'd be grateful if anyone would show
me the proper syntax for specifying exclusion of certain file types.
 
Thanks in advance for any help,
 
Zack
	[[alternative HTML version deleted]]

Do it in a two step process since you want the negation.
> x <- c('file1.xyz', 'file2.xml', 'file3.abc')
> x[-grep("xml$", x)]
[1] "file1.xyz" "file3.abc"
>

On Wed, Oct 1, 2008 at 12:33 AM, zack holden <zack_holden at hotmail.com>
wrote:
>
> Greetings R list,
>
> I am stuck on a simple syntax problem. I want to list all files in a
directory, excluding files of a certain type. I have tried pattern matching as
follows:
>
>
> a <- list.files(data, full.name = TRUE, pattern != ".xml")  #
exclude all .xml files
>
>
> The warning returns that my syntax is incorrect. I have read the regexpr
help files and search old posts to no avail. I'd be grateful if anyone would
show me the proper syntax for specifying exclusion of certain file types.
>
> Thanks in advance for any help,
>
> Zack
>        [[alternative HTML version deleted]]
>
> ______________________________________________
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http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?