R help - May 2007 - Cannot use an escape character in regexp

Given the string
> mystr <- "(Preconsuntivo  del  giorno gas 10 maggio 
2007)Tj"

I'm trying to detect and eliminate the string ")Tj" at the 
very end of mystr by means of 
gsub(rx2,"",mystr) BUT preparing the 
matching regexp string a warning pops up
> rx2 <- "\)Tj$"
Warning 
messages:
1: '\)' is an unrecognized escape in a character string 
2: 
unrecognized escape removed from "\)Tj$" 

and
> rx2
[1] ")Tj$"

I 
tried also rx2 <- "(\))Tj$" but the result is the same.

What am I 
missing?

Ciao
Vittorio

On 11/05/2007 7:07 AM, Vittorio wrote:
> Given the string
> 
>> mystr <- "(Preconsuntivo  del  giorno gas 10 maggio 
> 2007)Tj"
> 
> I'm trying to detect and eliminate the string ")Tj" at the 
> very end of mystr by means of 
> gsub(rx2,"",mystr) BUT preparing the 
> matching regexp string a warning pops up
> 
>> rx2 <- "\)Tj$"
> Warning 
> messages:
> 1: '\)' is an unrecognized escape in a character string 
> 2: 
> unrecognized escape removed from "\)Tj$" 
> 
> and
> 
>> rx2
> [1] ")Tj$"
> 
> I 
> tried also rx2 <- "(\))Tj$" but the result is the same.
> 
> What am I 
> missing?
You want the escaping to occur in gsub, not in R.  So you want to escape 
the escape:

rx3 <- "\\)Tj$"
gsub(rx3, "", mystr)

Duncan Murdoch