如何在 R markdown 中添加子图（bookdown）

Question

我正在尝试在 R bookdown 项目中添加带有子标题的图形，如下所示

---
output:
  pdf_document:
    extra_dependencies: "subfig"
---
     
```{r  echo=F, out.width = "50%",fig.showtext=TRUE,fig.show='hold',fig.cap="TITULO"}
par(mfrow=c(1,2))
knitr::include_graphics("ts_mult.png") 
knitr::include_graphics("ts_ad.png") 
```

我得到以下结果

然后我尝试如下添加子标题（“imagen a”、“imagen b”）

```{r  echo=F, out.width = "50%",fig.showtext=TRUE,fig.show='hold',fig.cap="TITULO",fig.subcap=c("imagen a", "imagen b")}
par(mfrow=c(1,2))
knitr::include_graphics("ts_mult.png") 
knitr::include_graphics("ts_ad.png") 
```

但这不起作用，它会引发以下错误

! Undefined control sequence.
<recently read> \subfloat 

Error: LaTeX failed to compile Tesis_AE.tex. See https://yihui.org/tinytex/r/#debugging for debugging tips.

如何正确添加子字幕？

Answer 1

你只需要在块中添加fig.subcap=c("A subtitle","Another subtitle")。

至少在我的环境中，fig.showtext=TRUE 不是必需的，而是会导致错误：Error in loadNamespace(name) : there is no package called 'showtext' Calls: <Anonymous> ... loadNamespace -> withRestarts -> withOneRestart -> doWithOneRestart Execution halted。这就是为什么我在答案中排除了该设置。

---
output:
  pdf_document:
    extra_dependencies: "subfig"
    keep_tex: yes
---
     
```{r echo=F, out.width = "50%",fig.show='hold',fig.cap="TITULO", fig.subcap=c("Subtitulo1","Subtitulo2")}
par(mfrow=c(1,2))
knitr::include_graphics("your-path-to/image1.png") 
knitr::include_graphics("your-path-to/image2.png") 
```

会话信息

> sessionInfo()
R version 4.0.2 (2020-06-22)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 18362)

Matrix products: default

locale:
[1] LC_COLLATE=Japanese_Japan.932  LC_CTYPE=Japanese_Japan.932    LC_MONETARY=Japanese_Japan.932
[4] LC_NUMERIC=C                   LC_TIME=Japanese_Japan.932    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

loaded via a namespace (and not attached):
[1] compiler_4.0.2 tools_4.0.2   

> rmarkdown::pandoc_version()
[1] ‘2.7.3’