[R] Obtain the hex code for a given character.
murdoch.duncan at gmail.com
Wed Feb 5 03:01:47 CET 2014
On 14-02-04 7:57 PM, Rolf Turner wrote:
> If I have a character such as "£" stored in a object called "xxx", how
> can I obtain the hex code representation of this character? In this
> case I know that the hex code is "\u00A3", but if I didn't, how would I
> find out?
charToRaw will give you the bytes used to store it:
 c2 a3
That was on MacOS, which uses UTF-8 encoding. On Windows, using Latin1,
You won't see 00A3, because that's not an encoding that R uses, that's
the Unicode "code point". It's not too hard to get to that from the
UTF-8 encoding, but I don't know any R function that does it.
> I would like a function "foo()" such that foo(xxx) would return, say,
> the string "00A3".
I don't know how to get that string, but as.character(charToRaw(x)) will
put the bytes for x in strings, e.g.
 "c2" "a3"
on a Mac.
> I have googled and otherwise searched around and have come up with
> nothing that seemed at all helpful to me. If I am missing something
> obvious, please point me at it.
> (I have found a table on the web, which contains the information that I
> need, but it is only accessible "by eye" as far as I can discern.)
> Supplementary question: Suppose I have the string "00A3" stored in
> an object called "yyy". How do I put that string together with "\u"
> so as to obtain "£"? I thought I could do
> xxx <- paste("\u",yyy,sep="")
> but R won't let me use "\u" "without hex digits". How can I get around
The \u notation with a code point is handled by the R parser, so you
need to parse that string, which means putting it in quotes first, e.g.
xxx <- eval(parse(text = paste0("'\\u", yyy, "'")))
That seems pretty excessive. You'd probably be better off doing all of
this in C instead...
> Rolf Turner
> R-help at r-project.org mailing list
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
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