On Thu, 12 Jun 2008, Henrik Bengtsson wrote:
A regular set is given by "[<set>]". The complementary set is given
by "[^<set>]" where <set> is a set of symbols. I don't think you have
to escape symbols in <set> (but I might be wrong).
This covered in ?regexp. The metacharacters in character classes (the
official name for your 'regular set') are ^]-\.
In any case, this does what you want:
lines <- c("abc", "!abc", "#abc", "^abc", " #abc")
pattern <- "^[^!#^]";
grep(pattern, lines, value=TRUE)
[1] "abc" " #abc"
/Henrik
On Thu, Jun 12, 2008 at 8:06 PM, Marc Schwartz
<[EMAIL PROTECTED]> wrote:
on 06/12/2008 08:42 PM Gundala Viswanath wrote:
Hi all,
I am trying to capture lines of a file that DO NOT
start with the following header: !, #, ^
But somehow my regex used under grep doesn't
work.
Please advice what's wrong with my code below.
__BEGIN__
in_fname <- paste("mydata.txt,".soft",sep="")
data_for_R <- paste("data_for_R/", args[3], ".softR", sep="")
# my regex construction
cat(temp[-grep("^[\^\!\#]",temp,perl=TRUE)], file=data_for_R, sep="\n")
dat <- read.table(data_for_R)
___END__
You need to double the escape character when being used to differentiate
meta-characters in a regex. Note also that the only meta-character in your
sequence is the carat ('^').
Lines <- c("! Not This Line", "# Not This Line", "^ Not This Line",
"This Line")
Lines
[1] "! Not This Line" "# Not This Line" "^ Not This Line"
[4] "This Line"
grep("^[!#\\^]", Lines)
[1] 1 2 3
Lines[-grep("^[!#\\^]", Lines)]
[1] "This Line"
HTH,
Marc Schwartz
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--
Brian D. Ripley, [EMAIL PROTECTED]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
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