ggplot2 - How to add labels to multiple plots figure?

问题

I need to add one x label and one y label to the following multiple plots figure using cowplot:

library(ggplot2
set.seed(99)

x_1 = data.frame(z = rnorm(100))
x_2 = data.frame(z = rnorm(100))
x_3 = data.frame(z = rnorm(100))

lst = list(x_1, x_2, x_3)

lst_p = list()

for (i in 1:length(lst)) {
    lst_p[[i]] = ggplot(data=lst[[i]], aes(lst[[i]]$z)) + 
    geom_histogram() +
        xlab("X LAB") +
        ylab("Y LAB") 
}

p_no_labels = lapply(lst_p, function(x) x + xlab("") + ylab(""))

title = cowplot::ggdraw() + cowplot::draw_label("test", size = 20)

p_grid = cowplot::plot_grid(plotlist = p_no_labels, ncol = 1)

print(cowplot::plot_grid(title, p_grid, 
                         ncol = 1, rel_heights = c(0.05, 1, 0.05)))

The x label should be at the bottom and the y label on the left.

Is there any quick way of doing this? Thanks

回答1:

If you do not need to use cowplot (most of the deficiencies it addressed are now a part of ggplot2), here is a solution:

df <- cbind(fct = rep(c('z1', 'z2', 'z3'), each = 100),
            val = rbind(x_1, z2 = x_2, z3 = x_3))
ggplot(df) +
    geom_histogram(aes(x = val)) +
    facet_wrap(vars(fct), nrow = 3) +
    labs(x = "X LAB", y = "Y LAB", title = "test") +
    theme(strip.background = element_blank(),
          strip.text = element_blank(),
          plot.title = element_text(hjust = 0.5))

来源：https://stackoverflow.com/questions/52666473/ggplot2-how-to-add-labels-to-multiple-plots-figure