如果我已经在使用构面并且不能再次使用它们，则与 ggarrange 的 y 轴范围相同

Question

my question is basically a follow-up to this question . However, the problem is that in the said question the answer completely bypasses the fact that ggarrange is used and instead transfers the whole issue to be handled by the facets functionality of ggplot.

This doesn't work for me since I already am using facets in the sub-plots and I cannot use them again.

Here is some example code. I am wondering how to achieve that the two plots which are joined with ggarrange have the same range of y-axis (of course, not setting the limits manually).

mtcars %>% 
  group_split(vs) %>% 
  map(~ggplot(., aes(x = mpg, y = wt)) +
        geom_point() +
        facet_grid(rows = vars(am), cols = vars(gear))) %>% 
  ggarrange(plotlist = .)

As you can see, the left image's y-axis ranges from 2 to 5, while the right plot's y-axis ranges from 1.5 to 3.5. How can I make them be the same?

Answer 1

I'm once again arguing for abandoning the 'ggarrange' approach, this time in favour of the {patchwork} package, which allows you to apply an operation to all previous plots. In this case, we can use & scale_y_continuous(limits =...) to set the limits for all plots.

library(ggplot2)
library(dplyr)
library(purrr)
library(patchwork)

mtcars %>% 
  group_split(vs) %>% 
  map(~ggplot(., aes(x = mpg, y = wt)) +
        geom_point() +
        facet_grid(rows = vars(am), cols = vars(gear))) %>% 
  wrap_plots() &
  scale_y_continuous(limits = range(mtcars$wt))

^{Created on 2022-12-08 by the reprex package (v2.0.0)}

Answer 2

One option would be to compute and add the range of your x and y variables to your dataset before splitting, which could then be used to set the limits.

library(dplyr)
library(ggplot2)
library(ggpubr)
library(purrr)

mtcars %>% 
  mutate(across(c(mpg, wt), list(range = ~list(range(.x))))) %>%
  group_split(vs) %>% 
  map(~ggplot(., aes(x = mpg, y = wt)) +
        geom_point() +
        scale_x_continuous(limits = .$mpg_range[[1]]) +
        scale_y_continuous(limits = .$wt_range[[1]]) +
        facet_grid(rows = vars(am), cols = vars(gear))) %>% 
  ggarrange(plotlist = .)