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

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   - Benjamin Franklin

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

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