[R] display double dot over character in plotmath?

[David Winsemius]

> On May 13, 2017, at 5:47 AM, Ranjan Maitra <maitra at email.com> wrote:
> 
> 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.

On a Mac it is cmd-u followed by the vowel of your choice. Perhaps you should do a google search on the topic of getting umlauted characters for the distro of your choice?

David.


> 
> Thanks again for your help, and best wishes,
> Ranjan
> 
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David Winsemius
Alameda, CA, USA