Hmm, this brings up an interesting question. What if the string I'm looking
for contains escape characters? For example, grep( paste( "^", "(ab)" ),
c("ab","(ab)") ) => c(1), not c(2).
I couldn't find an equivalent to Emacs's regexp-quote, which would let me
write regexp.quote("(ab)") => "\\(ab\\)". The syntax of regular expressions
is complicated enough that this is not trivial. Is there perhaps a CRAN
package with regular expression utilities?
-s
On Sat, Nov 29, 2008 at 7:12 AM, Gabor Grothendieck <[EMAIL PROTECTED]
> wrote:
> > a <- 2:3
> > b <- c("aaa 2 aaa", "2 aaa", "3 aaa", "aaa 3 aaa")
> > re <- paste("^(", paste(a, collapse = "|"), ")", sep = "")
> > grep(re, b, value = TRUE)
> [1] "2 aaa" "3 aaa"
>
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