Greek letters in ggplot2 titles and legends within knitr

[lhunsicker]

Is there an easier way to include a Greek letter mu in a ggplot2 figure legend (or title) within a knitr document? The usual knitr $\\mu$ is printed literally (without the duplicated backslash) within the ggplot2 figure. I also tried defining a phrase within the code block and then using that phrase within the ggplot function. But again the the $\\mu$ was printed literally (removing the duplicated backslash), not translated to the Greek mu. So apparently the $\\mu$ method doesn't work within a code block. I found a method that works defining a phrase within the code block using
expression(paste("Baseline insulin (", mu, "U/mL)"))
but this method would be cumbersome if one needed to use multiple Greek letters. Is there an easier way?
Thanks in advance for help with this!
Larry Hunsicker

[andresrcs]

You can use bquote()

library(ggplot2)

ggplot(iris, aes(Sepal.Length, Sepal.Width)) +
    geom_point() + 
    labs(
        title = bquote(Baseline~insulin(mu*U/mL))
        )

^{Created on 2020-06-21 by the reprex package (v0.3.0)}

[lhunsicker]

That does it. Thanks, andesrcs!

bquote is part of the base package. I found the documentation to be pretty obscure. It seems to assume an understanding of lisp. I found a clearer explanation of how this works at https://trinkerrstuff.wordpress.com/2018/03/15/2246/
This post also refers to plotmath {grDevices}.
Maybe this will help others trying to enter math symbols/language into r figure legends.