[R] Degree symbol as axis label superscript

[Bert Gunter]

True, but unnecessary with UTF-8 encodings of unicode (subject to some
caveats, though):

plot(1:5, runif(5),xlab = "Temp (°F)", ylab = "result")

should work fine, where the º ("degree") symbol was inserted by the
symbol insertion facility on my Mac. Windows has something similar.
See the comments in the plotmath documentation just before the
examples for more details on this, along with some caveats about the
need for a suitable display/plot device.

More laboriously, but perhaps more informatively, one can look up
"unicode code point for degree symbol" to find that it is decimal 176.
Then R's intToUtf8() function converts this to the UTF-8 encoding that
**should** display as a "degree" symbol, subject to the above
referenced caveats.
Hence:
> intToUtf8(176)
[1] "°"  ##degree character

## So, for example, you can do:
> degrF <-paste0(intToUtf8(176),"F")
> degrF
[1] "°F" ("degrees F")

> plot(1:5, runif(5),xlab = paste0("Temp (", degrF,")"), ylab = "result")

As Andrew said, you can use plotmath to do this, too; it just isn't
needed for simple insertion of "standard" symbols.

NOTE: As I am far from an expert on all of this, I would appreciate
clarification or correction of any errors or misstatements in the
above.

Bert Gunter


On Tue, Nov 30, 2021 at 11:34 AM Andrew Simmons <akwsimmo using gmail.com> wrote:
>
> Excuse my brevity, but take a look at ?plotmath
>
> It has tons of tips for making pretty labels
>
> On Tue, Nov 30, 2021, 14:05 Rich Shepard <rshepard using appl-ecosys.com> wrote:
>
> > I want to present the temperature on the Y-axis label as 'Water Temperature
> > (oC)' with the degree symbol as a superscript.
> >
> > My web search found a couple of methods; one put the entire example string
> > in the axis label, the other is close, but still incorrect.
> >
> > Source example:
> > #define expression with superscript
> > x_expression <- expression(x^3 ~ variable ~ label)
> > # The example axis label is:
> > 'X3 variable label' (with the 3 as a superscript)
> >
> > My use:
> > # Set degree symbol as superscript in plot's y axis:
> > y_expression <- expression(^o ~ C)
> >
> > R's error message:
> > Error in source("../scripts/all_temp_plots.r") :
> >    ../scripts/all_temp_plots.r:10:28: unexpected '^'
> > 9: # Set degree symbol as superscript in plot's y axis:
> > 10: y_expression <- expression(^
> >                                 ^
> >
> > What is the proper way to display a degree symbol in a plot's axis label?
> >
> > Rich
> >
> > ______________________________________________
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> > and provide commented, minimal, self-contained, reproducible code.
> >
>
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