Plotmath expression with mathematical operators in ggplot2

Question

I am still struggling with correct labels of my plots. I managed to get this to work.

df <-data.frame(a=seq(1,20),b=seq(1,20))
ggplot(df, aes(x = a, y = b)) + geom_point() +
  ylab(expression(paste(CH[4]~" formation rate"~"(",mu, mol, day^{-1},")")))

What it is missing is the operator sign " * " between mumol and day^-1. It should look like this: Thank you for your help.

Is `CH[4]~" formation rate"~"(",mu, mol%*%day^{-1},")"` not what you're looking for? — Jota, Jan 10 '17 at 11:11
thank you for your input. Your snippet produces: http://imgur.com/41mtmwZ Definitely progress, but not quite there. — nouse, Jan 10 '17 at 11:50
is this what you need `ylab(expression(CH[4]~formation~rate~(mu*mol~'*'~day^{-1})))` — Richard Telford, Jan 10 '17 at 12:40

score 6 · Accepted Answer · answered Jan 10 '17 at 15:46

I prefer not to use the paste style for expressions but to use ~ and * to separate terms with or without a space respectively. If you want an *, put it in quotes.

ggplot(df, aes(x = a, y = b)) + 
  geom_point() + 
  ylab(expression(CH[4]~formation~rate~(mu*mol~'*'~day^{-1})))

Plotmath expression with mathematical operators in ggplot2

1 Answers1