From: Gabor Grothendieck <ggrothendieck_at_gmail.com>

Date: Sat, 29 Nov 2008 18:51:07 -0500

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sat 29 Nov 2008 - 23:53:37 GMT

Date: Sat, 29 Nov 2008 18:51:07 -0500

grep has a fixed = TRUE argument if you want to ignore all regexp's.

On Sat, Nov 29, 2008 at 3:55 PM, Stavros Macrakis <macrakis_at_alum.mit.edu> wrote:

> 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
**> <ggrothendieck_at_gmail.com> 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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