Message-ID: <x24qj8k17d.fsf@biostat.ku.dk>
Date: 2004-11-29T17:35:34Z
From: Peter Dalgaard
Subject: escaping backslash in a string
In-Reply-To: <b3a7efa904112909201373cd6@mail.gmail.com>
Dan Lipsitt <danlipsitt at gmail.com> writes:
> How can I get a single backslash in a character string?
>
> My goal is to escape dots in a string that will be used as a regular
> expression. I thought I could do it this way:
>
> gsub(".", "\\.", x)
>
> Unfortunately, "\\" does not represent a literal backslash as I
> expected, but rather a pair of backslashes:
>
> > "\\."
> [1] "\\."
> > "\\"
> [1] "\\"
Nononononono.... If you want to know what is inside a string, use
cat() not (implicitly) print()
> cat( "\\.")
\.>
The thing is that print() itself escapes "weird" characters, including
the escape character:
> x <- readLines() # ctr-D terminates (on Linux anyway)
\.
> x
[1] "\\."
> Is there a way to represent "\"? This seems like a design problem in
> the interpreter.
Yes. Not at all.
--
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907