[R] display double dot over character in plotmath?

[Olivier Crouzet]

Hi,

The following simple solution gives appropriate results in base R (and
should work with any base character):

plot(rnorm(100), rnorm(100), main = expression(paste(omega, "\u0308")))

In your ggplot example, something like:

ggplot(data, aes(x=X)) + geom_line(aes(y = Z), size=0.43) + xlab
(expression(atop(top, bold(Age~paste(omega,"\u0308")))))

seems to produce what you need (AFAICT).

Note that, contrary to Robert's examples, one has to put
the corresponding diacritic AFTER the base character in unicode
conventions. Also, one needs to put the omega and "\u0308" within a 
paste() function in order to concatenate them correctly and to reach a
state in which they "combine" together.

Inserting this into your own code, the characters are not bold though
and I'm not sure what the solution would be. This may be an issue with
the font that is used. Also note that in order to export the graph to
pdf, you'd need to use cairo_pdf() in order to get the character
displayed correctly.

Olivier.


On Sun, 14 May 2017 10:43:40 -0500
Ranjan Maitra <maitra at email.com> wrote:

> Thanks, Duncan!
> 
> This works for the particular case and is, to my mind, a great
> solution!
> 
> However, I was wondering: is it possible to use these double dots
> with another character, such as omega?  
> 
> I apologize for changing the question somewhat, but I did not realize
> earlier that there were separate codes for putting double dots over
> different letters and I thought that figuring out the simpler
> question would be enough for me to figure out the next step. 
> 
> Thanks again!
> 
> Best wishes,
> Ranjan
> 
> 
> 
> On Sun, 14 May 2017 23:57:50 +1000 Duncan Mackay
> <dulcalma at bigpond.com> wrote:
> 
> > Hi
> > 
> > I just had to do something similar in windows with \"{u}. Try
> > Unicode symbol
> > - see ?plotmath 
> > 
> > ggplot(data, aes(x=X)) + geom_line(aes(y = Z), size=0.43) +
> > xlab(expression(atop(top,bold(Age~"\u00e4"))))
> > 
> > Regards
> > 
> > Duncan
> > 
> > Duncan Mackay
> > Department of Agronomy and Soil Science
> > University of New England
> > Armidale NSW 2351
> > Email: home: mackay at northnet.com.au
> > 
> > -----Original Message-----
> > From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of
> > Ranjan Maitra
> > Sent: Saturday, 13 May 2017 22:48
> > To: r-help at stat.math.ethz.ch
> > Subject: Re: [R] display double dot over character in plotmath?
> > 
> > On Fri, 12 May 2017 23:39:14 -0700 Daniel Nordlund
> > <djnordlund at gmail.com> wrote:
> > 
> > > On 5/12/17 4:55 PM, Ranjan Maitra wrote:
> > > > Hi,
> > > > 
> > > > Is it possible to display double dot (umlaut) over a character
> > > > such as
> > would be possible using \ddot x in LaTeX? I can do this using
> > tikzDevice but I wanted something simpler to point to.
> > > > 
> > > > Here is an example of what I would like to do, but it is not
> > > > quite
> > there:
> > > > 
> > > > require(ggplot2)
> > > > data<-as.data.frame(c("a","b","c","a","b","c"))
> > > > colnames(data)<-"Y"
> > > > data$X<-c(1:6)
> > > > data$Z<-c(1,2,3,1,2,3)
> > > > 
> > > > ggplot(data, aes(x=X)) + geom_line(aes(y = Z), size=0.43) +
> > xlab(expression(atop(top,bold(Age~"à"))))
> > > > 
> > > > I would like to put in a double dot over the "a" in the x-axis
> > > > instead
> > of "`".
> > > > 
> > > > Many thanks for any suggestions and best wishes,
> > > > Ranjan
> > > > 
> > > 
> > > You haven't told what OS you are using, but with Windows OS, you
> > > can get the 'ä' by making sure the NUMLOCK key is on, hold down
> > > the alt key and press 0228 on the numeric keypad.
> > > 
> > > 
> > 
> > I am sorry, I use a linux operating system. I use Fedora 25 but the
> > student I wanted to show this uses Ubuntu, though I don't know if
> > the distribution matters.
> > 
> > Thanks again for your help, and best wishes,
> > Ranjan
> > 
> > ______________________________________________
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> > 
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> > minimal, self-contained, reproducible code.
> > 
> 
> 
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-- 
  Olivier Crouzet, PhD
  /Assistant Professor/
  @LLING - Laboratoire de Linguistique de Nantes
    UMR6310 CNRS / Université de Nantes
  /Guest Researcher/
  @UMCG (University Medical Center Groningen)
    ENT department
    Reijksuniversiteit Groningen