Replace NAs in a list of ggplots with a dummy plot

Question

I have a list of plots that I would like to pass to patchwork::wrap_plots:

library(tidyverse)
library(patchwork)

# plots with na
dummy_plot <- ggplot() + theme_void()
p <- ggplot(mtcars, aes(mpg, cyl)) + geom_point()
plots <- list(p, p, NA)
patchwork::wrap_plots(plots)

Gives error:

Error: Only know how to add ggplots and/or grobs

I would therefore like to preprocess my list of plots to replace any NA with the blank dummy plot from above.

Desired outcome:

plots <- list(p, p, NA)
... some magic r code here to replace NA with dummy plot ...
# now plots looks like this    
plots <- list(p, p, dummy_plot)

I can now pass to wrap plots without error:

How can I replace instances of NA in a list to be my dummy plot?

Answer 1

You can loop over plots and check if the elements are identical to NA. If so, replace with dummy_plot

plots[sapply(plots, function(x) identical(x, NA))] <- list(dummy_plot)
patchwork::wrap_plots(plots)
# grid.rect(gp = gpar(fill = NA))

Result