ggplot2 error “invalid argument to unary operator”
I had a longish ggplot command and kept getting the error:
invalid argument to unary operator
It happened when I was specifying custom labels with scale_y_continuous but it turns out this was irrelevant and it hinged on a line break. It turnsout (at least when stepping through the code with ESS in Emacs using C-c C-c, bound to ess-eval-function-or-paragraph-and-step, you need to have the + of tying different ggplot bits together on the end of the preceding line.
This won’t work:
ggplot(longdata, aes(x=x, y = y)) + geom_jitter(alpha = 0.6)
This will:
ggplot(longdata, aes(x=x, y = y)) + geom_jitter(alpha = 0.6)
(Or, put it all on one line).