[Feature Request] Determine number of patches

[Nelson-Gon]

Hello,

Awesome package this! I would like to know if there could be a way to determine the number of patches of the current plot and/or access information on the layout. This would allow, among other things, looping over these patches.

My attempt at accessing these attributes

library(ggplot2)
library(patchwork)
p<-ggplot(mtcars,aes(mpg, disp)) +
  geom_col()
p1 <- ggplot(mtcars,aes(disp, mpg)) +
  geom_col()
p2<- p + p1
str(p2)

This contains the required information but there is no way to extract the number 2 without resorting to a RegEx based grep

A patchwork composed of 2 patches
- Autotagging is turned off
- Guides are kept

Layout:
2 patch areas, spanning 2 columns and 1 rows

    t l b r
1:  1 1 1 1
2:  1 2 1 2

length on the other hand gives 10 which is not ideal.

A solution

length(p2$patches$plots)

The above however will return only one plot if the plots are identical giving an incorrect length of 1.

p3 <- p + p
length(p3$patches$plots)

Thank you very much and apologies if this is documented/or exists somewhere else already ( I could not find them).

NelsonGon

[BioinformaNicks]

I tried length(composition_arranged$patches$layout$design) and it gave me the correct length.

Had the same issue: I did a seq_along(p3$patches$plots) only to discover that it did not count the last plot.

[seb-mueller]

Just banged my head against this as well, but @BioinformaNicks solutions doesn't seem to work for me, any other suggestions?:

library(ggplot2)
library(patchwork)
p<-ggplot(mtcars,aes(mpg, disp)) +
  geom_col()
p1 <- ggplot(mtcars,aes(disp, mpg)) +
  geom_col()
p2<- p + p1

p2$patches$layout$design
# NULL

[BioinformaNicks]

Just banged my head against this as well, but @BioinformaNicks solutions doesn't seem to work for me, any other suggestions?:

library(ggplot2)
library(patchwork)
p<-ggplot(mtcars,aes(mpg, disp)) +
  geom_col()
p1 <- ggplot(mtcars,aes(disp, mpg)) +
  geom_col()
p2<- p + p1

p2$patches$layout$design
# NULL

Perhaps the difference is that I typically use the plot_layout function to arrange my plots, and not the simple p1+p2 syntax?

[seb-mueller]

Maybe that's true, which would make an even a better case for unified and straightforward to use solution..