Patchwork legend collecting fails

Question

I have been trying to collect legends of plots created in a loop. However, this fails to produce the desired result, as the legends are not collected. I tried

(res[[1]] / res[[2]]) + plot_layout(guides = "collect") + theme(legend.position = "bottom") 

where res[[1]] and res[[2]] are list elements created in the loop.

Any advice would be much appreciated.

Resulting plot

Answer 1

Remove + theme(legend.position = "bottom"):

library(ggplot2)
library(patchwork)

p1 <- ggplot(data = mtcars, aes(x = disp, y = cyl, color = as.factor(vs))) +
  geom_point()
p2 <- ggplot(data = mtcars, aes(x = disp, y = cyl, color = as.factor(vs))) +
  geom_point()

p1 + p2 + plot_layout(guides = "collect")

Or if you'd like to place the legend in the center:

p1 + p2 + plot_layout(guides = "collect") & theme(legend.position = 'bottom')