On 02/05/2014 01:01 PM, Duncan Murdoch wrote:
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:
> charToRaw("£")
[1] c2 a3
That was on MacOS, which uses UTF-8 encoding. On Windows, using Latin1,
> charToRaw("£")
[1] a3
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.
as.character(charToRaw("£"))
gives
[1] "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
this?
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...
Hi Rolf,
I almost got it in Linux with:
x<-\u00A3
paste("\\u",
toupper(paste(as.character(charToRaw(x)),sep="",collapse="")),
sep="",collapse="")
[1] "\\uC2A3"
But I couldn't get rid of the double backslash, so I must agree with
Duncan. Also, I don't know how the "C2" gets in there.
Jim
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