[R] Transferring commas in character vector to expression

[Duncan Mackay]

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 at 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
>
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