Add secondary axis as a dual axis in R plot

Question

Hi, I just started learning R. Can someone help how to add 3 axis i.e wrt 3 variables to a plot?

Answer 1

You can add a secondary axis in ggplot by using sec.axis attribute in scale_* functions.

ggplot object + scale_x_continuous(sec.axis = axis calculation)

Ex:

> plot + scale_y_continuous(sec.axis = ~ .+2)