A) you wrote // when you meant \\. This behavior does not apply to forward
slash.
B) if you want the ability to represent any arbitrary character in a string,
some version of this feature is required. Visual Basic doesn't allow arbitrary
characters unless you concatenate chr() function calls, though it does allow
you to embed quotes (") by repeating them (""), sort of like \\, but much less
useful.
Learning to understand escaping is a significant step, because it occurs in
both the parsing of string literals and in regular expressions. Since
specifying a regex often involves using a string literal to specify a regex,
you have to escape the escape characters. Once you realize how useful this is
you never want to return to the "simplicity" of VB, and "simplifying" the R
language doesn't seem so attractive anymore.
So, just remember that \ is special in strings, and go reread the documentation
whenever it crops up to figure out what should go after it to get a particular
character into the string, and remember that a regex gets processed by two
different sets of rules one after the other.
---------------------------------------------------------------------------
Jeff Newmiller The ..... ..... Go Live...
DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go...
Live: OO#.. Dead: OO#.. Playing
Research Engineer (Solar/Batteries O.O#. #.O#. with
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Gene Leynes <gleyne...@gmail.com> wrote:
I think that people are afraid to say "You can't do that in R"...
But I think the real answer is: you can't do that in R.
Although, it is helpful to understand Jeff's reply. I hadn't fully realized
why this particular problem occurs before reading that. It's odd to me that //
and / are both stored as /, but that makes sense given my experience in R.
Also, the other replies are good advice, working with R's path functions or
sticking with forward slashes is the way to go (don't fight the assimilation,
the borg needs you).
Personally, I think some of these seemingly small problems actually encumber
R's mainstream adoption quite a bit, but then I'm not the one writing R. Plus,
it's is still pretty dang awesome even with its minor annoyances.
On Fri, Nov 4, 2011 at 8:45 AM, Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote:
Your str does not have any double backslashes to replace. You need to revisit
the concept of escape characters in the documentation. In brief, every "\\" in
a quoted string is actually a single character as stored in memory.
---------------------------------------------------------------------------
Jeff Newmiller The ..... ..... Go Live...
DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go...
Live: OO#.. Dead: OO#.. Playing
Research Engineer (Solar/Batteries O.O#. #.O#. with
/Software/Embedded Controllers) .OO#. .OO#. rocks...1k
---------------------------------------------------------------------------
Sent from my phone. Please excuse my brevity.
Kay Cichini <kay.cich...@uibk.ac.at> wrote:
I want to replace \\ with \ in:
str <-
"C:\\DOKUME~1\\u0327336\\LOKALE~1\\Temp\\RtmpQ5NJ8X\\TIRIS_PICS\\1_Img.jpg"
and tried:
gsub("\\\\", "\\", str)
but this removes the \\ without replacing them by \
Any help much appreciated,
Kay
-----
------------------------
Kay Cichini
Postgraduate student
Institute of Botany
Univ. of Innsbruck
------------------------
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