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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