Question

I have a ggplot where I have used expression(phantom(x) >=80) in the label text to get a proper greater-than-or-equal symbol.

However I also need to have (N=…) immediately underneath:

require(ggplot2)
.d <- data.frame(a = letters[1:6], y = 1:6)

labs <- c("0-9\n(N=10)","10-29\n(N=10)","30-49\n(N=10)", +
   "50-64\n(N=10)","65-79\n(N=10)", expression(phantom(x) >=80))

ggplot(.d, aes(x=a,y=y)) + geom_point() + 
   scale_x_discrete(labels = labs)

How can I combine the expression() with the escape \n ?

Answer 1

As @otsaw said in his answer to your earlier question, plotmath (and therefore expression) doesn’t allow linebreaks.
However, as a hack, you can use atop to let ≥80 appears on top of (N=10). But as you will soon see it doesn’t match with the other labels:

labs <- c("0-9\n(N=10)","10-29\n(N=10)","30-49\n(N=10)", 
          "50-64\n(N=10)","65-79\n(N=10)", 
          expression(atop(phantom(x) >=80, (N==10))))

So, as a further hack, you can pass the other labels as expressions:

labs <- c(expression(atop(0-9,(N==10))),expression(atop(10-29,(N==10))),
          expression(atop(30-49,(N==10))), expression(atop(50-64,(N==10))),
          expression(atop(65-79,(N==10))), expression(atop(phantom(x) >=80, (N==10))))

But of course you have @otsaw solution (using Unicode) that is considerably less wordy:

labs <- c("0-9\n(N=10)","10-29\n(N=10)","30-49\n(N=10)", 
          "50-64\n(N=10)","65-79\n(N=10)", 
          "\u2265 80\n(N=10)")