R：如何让 ggplot2::geom_text() 与其他格式的文本一起插入换行符？

Question

I am trying to put annotation in a faceted boxplot using the method described in the top answer of this question: Annotating text on individual facet in ggplot2

And formatting the text using methods picked up here: https://ggplot2.tidyverse.org/reference/annotate.html

I can't seem to figure out why geom_text() will not insert the line break in my code where I have place a \n . Here is a simplified version:

p.data <- data.frame(Main = rep("Ratio", 100),
                     CAT = c('A','B','C','D'),
                     value = rnorm(100, mean = 1.5, sd = 1.5))
p.text <- data.frame(Main = "Ratio",
                     CAT = 'B',
                     value = 7,
                     lab = "Text")
p <-  ggplot(data = p.data, aes(x = CAT, y = value, fill = CAT)) +
      geom_boxplot() +
      scale_y_continuous(breaks = c(0:6), limits = c(0,8)) +
      facet_wrap(~ Main, scales = 'fixed', nrow = 1, ncol = 1) +
      geom_text(data = p.text, hjust = 0, parse = TRUE,
                label = "paste(bold(CMV): f ^ 2, \" = 0.04, p = 0.003\", \n bold(MDD): n.s.)")
p

Among some other nonsense, I have tried:

label = "paste(bold(CMV): f ^ 2, \" = 0.04, p = 0.003\", \n bold(MDD): n.s.)"
label = "paste(bold(CMV): f ^ 2, \" = 0.04, p = 0.003\", \n, bold(MDD): n.s.)"
label = "paste(bold(CMV): f ^ 2, \" = 0.04, p = 0.003\", \"\n\", bold(MDD): n.s.)"
label = "paste(bold(CMV): f ^ 2, \" = 0.04, p = 0.003\", \"\n bold(MDD): n.s.\")"
label = "paste(bold(CMV): f ^ 2, \" = 0.04, p = 0.003\"\n, bold(MDD): n.s.)"

...but nothing has worked.

In case it is not obvious, what I want is the CMV results on one line and MDD results on another line, while keeping the bold fonts and superscripted "2". My final graph will consist of one graph with one facet and one with three facets stuck together using grid.arrange() , but my example is just the one graph.

Thanks

Answer 1

There are a couple of work around solutions:

@eipi10 suggests in the comment above using atop() :

p.data <- data.frame(Main = rep("Ratio", 100),
                 CAT = c('A','B','C','D'),
                 value = rnorm(100, mean = 1.5, sd = 1.5))
p.text <- data.frame(Main = "Ratio",
                 CAT = 'B',
                 value = 7,
                 lab = "Text")
p <- ggplot(data = p.data, aes(x = CAT, y = value, fill = CAT)) +
     geom_boxplot() +
     scale_y_continuous(breaks = c(0:6), limits = c(0,8)) +
     facet_wrap(~ Main, scales = 'fixed', nrow = 1, ncol = 1) +
     geom_text(data = p.text, hjust = 0, parse = TRUE,
               label = "atop(paste(bold(CMV): f ^ 2, \" = 0.04, p = 0.003\"), 
                             bold(MDD): n.s.)")
p

However, I am being picky about formatting and would like both lines to be left aligned. So, I will just create another line in the p.text data frame with a lower value to place another geom_text :

p.text <- data.frame(Main = "Ratio",
                     CAT = 'B',
                     value = c(7, 6),
                     lab = "Text")
p <- ggplot(data = p.data, aes(x = CAT, y = value, fill = CAT)) +
  geom_boxplot() +
  scale_y_continuous(breaks = c(0:6), limits = c(0,8)) +
  facet_wrap(~ Main, scales = 'fixed', nrow = 1, ncol = 1) +
  geom_text(data = p.text[1,], hjust = 0, parse = TRUE,
            label = "paste(bold(CMV): f ^ 2, \" = 0.04, p = 0.003\")") +
  geom_text(data = p.text[2,], hjust = 0, parse = TRUE,
            label = "paste(bold(MDD): n.s.)")
p

I'll have to adjust the value to get the line spacing just right, but this will work.