Axis label specifications in ggplot

Question

I'm attempting to have a two-line y-axis label that contains a superscript in ggplot and I am struggling.

I want the y axis label to say “[3H]ASEM binding (pmol/g)” with the 3 superscripted and (pmol/g) on a separate line.

This is what I have tried so far:

labs(x="", y=expression(paste("[" ^3 "H] ASEM Binding \n (pmol/g)"))) 

And it's given me the error "unexpected string constant"

Any suggestions?

Answer 1

You need an empty ''(2 single quotes) prior to the ^3.

  ggplot(sample_data, aes(x, y)) +
  geom_point() +
  labs(
    x = "",
    y = expression(atop(paste("[", ''^3, "H] ASEM Binding"), "(pmol/g)"))
  )

Another alternative is:

y = expression(atop("["^3*"H] ASEM Binding", "(pmol/g)"))