带 ggplot2 的辅助 x 轴

Question

I have the following data frame:

PhiSize	CumVol	Group
11.40	0.08	a
11.15	0.15	a
10.91	0.21	a
10.68	0.25	b
10.44	0.29	b
10.20	0.32	c
9.95	0.38	c

What i want to plot is a line-plot that has a secondary axis like the one above:

So far i did

library(ggplot2)

df <- data.frame(read_csv("file")

ggplot(aes(x = PhiSize, y = CumVol, color = Group ), data = df) +
  geom_line() +
  scale_x_reverse()

And got the following plot:

But when i add the last line:

ggplot(aes(x = PhiSize, y = CumVol, color = Group ), data = df) +
  geom_line() +
  scale_x_reverse()+
  sec_axis(2^(-df$PhiSize),name = "new")

It throws:

Error: Can't convert a double vector to function

I would like to get some help, please.

Answer 1

ggplot(aes(x = PhiSize, y = CumVol, color = Group ), data = df) +
  geom_line() +
  scale_x_reverse(sec.axis = sec_axis(~ 2^(-.),
    breaks=scales::log_breaks(n = 10), labels = scales::label_number()))