[R] grep triggering error on unicode character

[Dennis Fisher]

Colleagues,

[R 2.11; OS X]

I am processing a file on the fly that contains the following text:
	XXXáá 
[email clients may display this differently -- the string is three X's followed by two instances of the letter a with an acute accent]
I read the file with:
	X	<- readLines(FILENAME)
In this instance, the text of interest is on line 213.  When I examine line 213, it reads:
	XXX\xe1\xe1
This makes sense because the unicode mapping for á [a-acute] is U+00E1.

The problem arises when I attempt to manipulate the text in the file.  For example:
	> grep("XXX", X[213])
	integer(0)
	Warning message:
	In grep("XXX", X[213]) : input string 1 is invalid in this locale
Worse, yet:
	> tolower(X[213]) 
	Error in tolower(X[213]) : invalid multibyte string 1 

I am focussing on resolving the first problem, i.e., identifying a line containing XXX.  If I can do so, I can remove the offending lines before I execute the tolower command.
However, I am stumped as to how to resolve either problem.

Any help would be appreciated.

Thanks.

Dennis

Dennis Fisher MD
P < (The "P Less Than" Company)
Phone: 1-866-PLessThan (1-866-753-7784)
Fax: 1-866-PLessThan (1-866-753-7784)
www.PLessThan.com