Can't set limits for a graph with two y scales-CodePudding

I'm trying to plot a graph with two y scales. For this I use the following code

ggplot()  
    geom_line(data=plot_df_AIC, aes(x=x, y=AIC), color="red")  
    geom_line(data=plot_df_AUC, aes(x=x, y=AUC * 100), color="blue") 
    scale_y_continuous(sec.axis = sec_axis(~ ./100, name = "AUC")) 
  theme(
    axis.title.y = element_text(color = "red"),
    axis.text.y = element_text(color = "red"),
    axis.title.y.right = element_text(color = "blue"),
    axis.text.y.right = element_text(color = "blue")
  )

For the following data:

plot_df_AIC <- structure(list(x = 1:20, AIC = c(192.456332156948, 168.077664220646, 
151.620951957096, 147.718795436845, 137.444555845433, 100.40879221819, 
88.9138697158594, 71.0234955371967, 72.5073961740955, 74.8647755955335, 
75.3407718929883, 77.1002885963888, 70.2411723351313, 65.2276698782054, 
67.1077811158141, 67.4423951246628, 70.9441943080796, 59.719536949467, 
66.5031973889088, 68.8315706852903)), class = "data.frame", row.names = c(NA, 
-20L))

plot_df_AUC <- structure(list(x = 1:20, AUC = c(0.909483122312676, 0.932209889236273, 
0.946715923961602, 0.947250775396187, 0.956010866304684, 0.976934635048469, 
0.984366535772596, 0.98835498803627, 0.987203119638685, 0.985956953919869, 
0.986202696910042, 0.986506880115857, 0.982118157079483, 0.982189861532493, 
0.981637889799519, 0.977055762590389, 0.971319454724046, 0.965993970736366, 
0.953737877822623, 0.946781893644707)), class = "data.frame", row.names = c(NA, 
-20L))

And getting following output:

I would like to change the AUC y limits. For this I am passing an argument limits = c(0.8, 1) into scale_y_continuous. But after that I get an error:

ERROR while rich displaying an object: Error in seq.default(range[1], range[2], length.out = self$detail): 'from' must be a finite number

Traceback:
1. tryCatch(withCallingHandlers({
 .     if (!mime %in% names(repr::mime2repr)) 
 .         stop("No repr_* for mimetype ", mime, " in repr::mime2repr")
 .     rpr <- repr::mime2repr[[mime]](obj)
 .     if (is.null(rpr)) 
 .         return(NULL)
 .     prepare_content(is.raw(rpr), rpr)
 . }, error = error_handler), error = outer_handler)
2. tryCatchList(expr, classes, parentenv, handlers)
3. tryCatchOne(expr, names, parentenv, handlers[[1L]])
4. doTryCatch(return(expr), name, parentenv, handler)
5. withCallingHandlers({
 .     if (!mime %in% names(repr::mime2repr)) 
 .         stop("No repr_* for mimetype ", mime, " in repr::mime2repr")
 .     rpr <- repr::mime2repr[[mime]](obj)
 .     if (is.null(rpr)) 
 .         return(NULL)
 .     prepare_content(is.raw(rpr), rpr)
 . }, error = error_handler)
6. repr::mime2repr[[mime]](obj)
7. repr_text.default(obj)
8. paste(capture.output(print(obj)), collapse = "\n")
9. capture.output(print(obj))
10. evalVis(expr)
11. withVisible(eval(expr, pf))
12. eval(expr, pf)
13. eval(expr, pf)
14. print(obj)
15. print.ggplot(obj)
16. ggplot_build(x)
17. ggplot_build.ggplot(x)
18. layout$setup_panel_params()
19. f(..., self = self)
20. Map(setup_panel_params, scales_x, scales_y)
21. mapply(FUN = f, ..., SIMPLIFY = FALSE)
22. (function (scale_x, scale_y) 
  . {
  .     self$coord$setup_panel_params(scale_x, scale_y, params = self$coord_params)
  . })(dots[[1L]][[1L]], dots[[2L]][[1L]])
23. self$coord$setup_panel_params(scale_x, scale_y, params = self$coord_params)
24. f(..., self = self)
25. view_scales_from_scale(scale_y, self$limits$y, self$expand)
26. view_scale_secondary(scale, limits, continuous_range)
27. scale$secondary.axis$break_info(continuous_range, scale)
28. f(..., self = self)
29. self$mono_test(scale)
30. f(..., self = self)
31. seq(range[1], range[2], length.out = self$detail)
32. seq.default(range[1], range[2], length.out = self$detail)
33. stop("'from' must be a finite number")

What should I do to correctly change the limits of this axis?

CodePudding user response：

You can't set limits for the secondary axis via the limits argument.

If you want a different scale or limits for the secondary axis you have to scale your data accordingly. My code below makes use of scales::rescale to do the (re-)scaling of your AUC data:

library(ggplot2)

from <- c(0.8, 1)
to <- range(plot_df_AIC$AIC)
plot_df_AUC$AUC <- scales::rescale(plot_df_AUC$AUC, from = from, to = to)

ggplot()  
  geom_line(data=plot_df_AIC, aes(x=x, y=AIC), color="red")  
  geom_line(data=plot_df_AUC, aes(x=x, y=AUC), color="blue") 
  scale_y_continuous(sec.axis = sec_axis(
    ~ scales::rescale(.x, to = from, from = to), name = "AUC")) 
  theme(
    axis.title.y = element_text(color = "red"),
    axis.text.y = element_text(color = "red"),
    axis.title.y.right = element_text(color = "blue"),
    axis.text.y.right = element_text(color = "blue")
  )