How do I add a superscripted comma and a space in a ggplot2 axis tick label?

Question

I am trying to add superscripts to my y axis tick labels in ggplot2. I want the labels to look like this:

ATRS2^0m,0f (where the 0f and 0m are superscripted). This produces an error that looks like this.

Error in parse(text = levels(diff_30$Station)) :
<text>:1:8: unexpected symbol
1: ATRS2^0m0f ^

I realize that what I am parsing is not an R expression of any sort, which is why it is failing. But how do I get this to work? There must be some way.

My code to create the label looks like this:

paste(missing_df$Station,paste('^',missing_df$Precip_30_m,"m,",missing_df$TMin_30_f,"f",sep=''),sep='')

My ggplot code to plot and produce the labels looks like this.

plot + scale_y_discrete(labels = parse(text = levels(diff_30$Station)))

I've tried using this, but that fails. I've looked at bquote, which might work, but that syntax is confusing me even more.

plot + scale_y_discrete(labels = expression(parse(text = levels(diff_30$Station))))

Any help would be wonderful. Thank you!

Answer 1

Let's see if the next piece of code does the trick you are looking for:

data("iris")

#vector from factor levels 
strtest <- levels(iris$Species)

#We build the "label" and leave the result as a list
labels <- lapply(strtest, function(x) bquote(.(x)^'0m,0f'))

#Plotting
ggplot(iris,aes(x = Sepal.Length, y = Species))+
  geom_point() +
  #we use do.call to "apply" function 'expression' to each element of the list label
  scale_y_discrete(labels=do.call(expression,labels))

Result: