如何在 ggplot2' geom_label 注意：此问题已更新，因此请参阅“编辑”

问题描述

注意：此问题已更新，因此请参阅“编辑”

我正在使用 ggplot2 绘制带有一些注释的条形图。我想在数学符号代码（即 \n）前后添加换行符 (%down%)。但是，paste(...,sep = "\n") 中的 geom_label(aes(label=paste(...))) 失败并出现以下错误：Error in parse(text = text[[i]]) : <text>:2:1: unexpected SPECIAL。我该怎么办？

---
output: 
  bookdown::pdf_document2:
    latex_engine: xelatex
    keep_tex: true
    dev: cairo_pdf
---
knitr::opts_chunk$set(
  dev      = "cairo_pdf",dev.args = list(family = "Roboto Medium")
  )
library(tidyverse)
library(magrittr)
tibble(
  F1 = factor(
    c(-0.5,-0.5,0.5,0.5),levels = c(-0.5,labels = c("A","H")
  ),F2 = factor(
    c(-0.5,levels=c(-0.5,labels=c("A",pct = c(60,20,40,20)
) %>% 
  ggplot(
    .,aes(
      x = F1,y = pct,color = F2,fill = F2
    )
  )+
  geom_bar(
    stat="identity",width = 0.6,position = position_dodge(width = 0.7)
  ) +
  geom_label(
    parse = TRUE,aes(
      label = paste(
        sep = "",# "\n"
        F1,"%down%",F2
      ),vjust = -1
    ),position = position_dodge2(
      width = 1 
    ),fill = "white",colour = "black",label.size = NA,size = 5
  ) 

编辑

虽然@the-mad-statter 的 answer 非常有用并且使我能够添加换行符，但向下箭头字符 \u2193 没有出现，因为我在图表中使用的字体没有似乎有\u2193。我通过指定 knitr::opts_chunk$set(dev.args = list(family = "Roboto Medium")) 来使用 Roboto Medium。

解决方法

似乎对我有用的是将 showtext 包与所需的 Unicode 符号结合使用：

---
output: 
  bookdown::pdf_document2:
    latex_engine: xelatex
    keep_tex: true
    dev: cairo_pdf
---

```{r setup,include=FALSE}
knitr::opts_chunk$set(
  echo     = FALSE,dev      = "cairo_pdf",dev.args = list(family = "Roboto")
)

library(tidyverse)

library(showtext)
font_add_google("Roboto")
showtext_auto()
```

```{r}
tibble(
  F1 = factor(
    c(-0.5,-0.5,0.5,0.5),levels = c(-0.5,labels = c("A","H")
  ),F2 = factor(
    c(-0.5,levels=c(-0.5,labels=c("A",pct = c(60,20,40,20)
) %>% 
  ggplot(
    .,aes(
      x = F1,y = pct,color = F2,fill = F2
    )
  )+
  geom_bar(
    stat="identity",width = 0.6,position = position_dodge(width = 0.7)
  ) +
  geom_label(
    parse = FALSE,aes(
      label = paste(
        sep = "\n",F1,"\u2193",F2
      ),vjust = -1
    ),position = position_dodge2(
      width = 1 
    ),fill = "white",colour = "black",label.size = NA,size = 5
  )
```