Duncan,

Thanks! That was the tip I needed. With that, I was able to get this to
work perfectly:

x.lab <- c("a*a", "bbb", "c,cc*c", "d,dd")
x.lab <- gsub("\\*", "*Delta*", x.lab)
x.lab <- gsub(",", "*symbol(\"\\\\54\")*", x.lab)
dotchart(1:length(x.lab), labels = parse(text = x.lab))



On Sat, Jul 6, 2013 at 9:38 PM, Duncan Mackay <mackay@northnet.com.au>wrote:

>  Eric
>
> How does this look - (you might have to add a few symbol("\54")  where
> needed for me this give a comma on windows7  ver 3.1
>
>  xyplot(1:4 ~ 1:4, scales = list(x=list(at = 1:4, labels =
> c(expression(a*a),expression(bbb),expression(c*Delta*cc*c),expression(d*Delta*symbol("\54")*dd)
> ) ) ) )
>
> I mostly use lattice and have forgotten how to do labels in basic plot so
> have used lattice. should be similar and you can modify to suit.
>
> It was trial and error in going up through the numbers  from about 38
>
>
> Duncan
>
> At 11:57 7/07/2013, you wrote:
>
> Duncan,
>
> Thanks for the suggestion, but that won't work for my situation. I'm
> trying to use a character vector to label some axis ticks. There are some
> elements in the vector that have either a comma, or both Greek symbols and
> a comma, like the the third and fourth elements in x.lab below:
>
> > x <- 1:4
> > x.lab <- c("a*a", "bbb", "c,cc*c", "d,dd")
> > x.lab <- gsub("\\*", "*Delta*", x.lab)
> > x.lab <- parse(text = x.lab)
> Error in parse(text = x.lab) : <text>:3:2: unexpected ','
> 2: bbb
> 3: c,
>    ^
> > dotchart(x, labels = x.lab)
>
> The root problem that I'm stumped on is how to either:
> 1) insert a comma into an expression and have it be read as a valid
> character, or
> 2) replace the comma in the character string with 'list(a, b, c)' as in
> the help for plotmath and have it interpreted correctly.
>
> Cheers,
> eric
>
>
> On Sat, Jul 6, 2013 at 3:33 PM, Duncan Mackay <mackay@northnet.com.au >
> wrote:
>  Hi Eric
>
> I have not been following the thread but following on what David has said
> on previous occasions
>
> try for example
>
> plot(1,1, ylab =  expression("aa aaa,aa bb"*Delta*"b cccc"*Delta*"cc, c") )
>
> Below is from a partly saved previous post of David's several months ago
> which may give you some ideas
>
> DATA_names<-c(
> "A mg kg",
> "B mg kg",
> "C mg kg",
> "D mg kg",
> "E mg kg",
> "F mg kg",
> "G mg kg",
> "H mg kg")
>
> pos <- barplot(1:length(DATA_names))
> text(x=pos,y=-1, xpd=TRUE, srt=45,
>                     labels= sapply( gsub("mg kg", "(mg kg)^-1",
> DATA_names),
>                                     as.expression))
>
> HTH
>
> Duncan
>
>
> Duncan Mackay
> Department of Agronomy and Soil Science
> University of New England
> Armidale NSW 2351
> Email: home: mackay@northnet.com.au
>
>
>
>
> At 07:47 6/07/2013, you wrote:
>  I'm trying to format a given character vector as an expression with Greek
> symbols to be used in labeling axis ticks. Thanks to some help from David
> Winsemius, I've learned how to make the substitution and place the Greek
> symbols in, however I've run into another problem: Some of my labels have
> commas in them, so when the parse command is executed, there is an
> unexpected symbol error. For example:
>
> > x <- c("aa", "aaa,aa", "bb*Delta*b", "cccc*Delta*cc,c")
> > parse(text = x)
> Error in parse(text = x) : <text>:2:4: unexpected ','
> 1: aa
> 2: aaa,
>      ^
>
> I've tried various iterations of wrapping the commas in interior quotes
> ("aaa\",\"aa"), but then the error shifts to the quote. I see in plotmath
> that 'list(a,b,c)' gives me comma separated values, but I haven't been able
> to work out how to get this construction for elements that have a comma.
>
> Is this possible?
>
> --
>
> Eric Archer, Ph.D.
> Southwest Fisheries Science Center
> NMFS, NOAA
> 8901 La Jolla Shores Drive
> La Jolla, CA 92037 USA
> 858-546-7121 (work)
> 858-546-7003 (FAX)
>
> Marine Mammal Genetics Group: swfsc.noaa.gov/prd-mmgenetics
> ETP Cetacean Assessment Program: swfsc.noaa.gov/prd-etp
>
> "The universe doesn't care what you believe.
>  The wonderful thing about science is that it
>    doesn't ask for your faith, it just asks
>    for your eyes."  - Randall Munroe
>
> "Lighthouses are more helpful than churches."
>    - Benjamin Franklin
>
>    "...but I'll take a GPS over either one."
>        - John C. "Craig" George
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
>  https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>
>
>
>
>
> --
>
> Eric Archer, Ph.D.
> Southwest Fisheries Science Center
> NMFS, NOAA
> 8901 La Jolla Shores Drive
> La Jolla, CA 92037 USA
> 858-546-7121 (work)
> 858-546-7003 (FAX)
>
> Marine Mammal Genetics Group: swfsc.noaa.gov/prd-mmgenetics
> ETP Cetacean Assessment Program: swfsc.noaa.gov/prd-etp
>
> "The universe doesn't care what you believe.
>  The wonderful thing about science is that it
>    doesn't ask for your faith, it just asks
>    for your eyes."  - Randall Munroe
>
> "Lighthouses are more helpful than churches."
>    - Benjamin Franklin
>
>    "...but I'll take a GPS over either one."
>        - John C. "Craig" George
>
>


-- 

Eric Archer, Ph.D.
Southwest Fisheries Science Center
NMFS, NOAA
8901 La Jolla Shores Drive
La Jolla, CA 92037 USA
858-546-7121 (work)
858-546-7003 (FAX)

Marine Mammal Genetics Group: swfsc.noaa.gov/prd-mmgenetics
ETP Cetacean Assessment Program: swfsc.noaa.gov/prd-etp

"The universe doesn't care what you believe.
 The wonderful thing about science is that it
   doesn't ask for your faith, it just asks
   for your eyes."  - Randall Munroe

"Lighthouses are more helpful than churches."
   - Benjamin Franklin

   "...but I'll take a GPS over either one."
       - John C. "Craig" George

	[[alternative HTML version deleted]]

