Rmarkdown：同一页面上的多个图，带有单独的标题

Question

我写中的R与降价一个pdf输出的报告。我有几个情节，我想每个网页上显示四个图在一个2x2矩阵布局。有没有一种方法，让他们像显示与独立的字幕？ P>

这是我迄今为止尝试过的：

• 包gridExtra - ？我可以很容易地设置布局我想，但我没能字幕添加到plots.Is有一个选项，以字幕添加到grid.arrange P>剧情

• 放置各小区在不同的块和有R块选择播放。基本上设置out.width='.49\\linewidth', fig.align='right'和fig.align='left'替代地。在这里，我可以单独设置字幕与fig.cap但该地块始终显示在单独的页面。

• 我试图用fig.width玩，fig.height选项，并能够让他们到显示在同一页面上各自的左侧或页的右侧。然而，标题总是发生在中心的整个页面宽度和住宿，而不是与剧情大小包裹。有没有一种方法，使字幕跟随剧情大小规则？

这是一个示例代码：

```{r, echo=FALSE, cache=FALSE, results=FALSE, warning=FALSE,  comment=FALSE, message= FALSE, eval =T, fig.height= 9}

p1<- ggplot(mpg, aes(displ, hwy, colour = class)) + 
geom_point()+
labs(caption = "Lorem ipsum dolor sit amet, consectetur adipiscing     elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. ")+
theme(plot.caption = element_text(hjust = 0.5))

p2<- ggplot(mpg, aes(displ, hwy, colour = class)) + 
geom_point()+
labs(caption = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.  ")+
theme(plot.caption = element_text(hjust = 0.5))

p3<- ggplot(mpg, aes(displ, hwy, colour = class)) + 
geom_point()+
labs(caption = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. ")+
theme(plot.caption = element_text(hjust = 0.5))

p4<- ggplot(mpg, aes(displ, hwy, colour = class)) + 
geom_point()+
labs(caption = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. ")+
theme(plot.caption = element_text(hjust = 0.5))

library(gridExtra)
grid.arrange(p1,p2,p3,p4)
```

我会很感激任何帮助。谢谢！

Answer 1

您可以在 LaTeX 输出中使用子图，如 here 所述。如果您有很多情节并且想要更轻松地提供字幕，您可以在块之前的列表中指定这些（即captions <- c("Caption 1", "Caption 2"），并将此列表提供给块fig.subcap=captions

---
output: pdf_document
header-includes:
  - \usepackage{subfig}
---  

```{r}
captions <- c("Caption 1",
              "Caption 2", 
              "Caption 3",
              "Caption 4: a very very very very very very very very very long one")
```


```{r, echo=FALSE, cache=FALSE, results=FALSE, warning=FALSE,  comment=FALSE, message= FALSE, eval =T,  fig.cap = "Overall Caption", fig.subcap=captions, out.width='.49\\linewidth', fig.asp=1, fig.ncol = 2}
library(ggplot2)
p1<- ggplot(mpg, aes(displ, hwy, colour = class)) + 
geom_point()+
theme(plot.caption = element_text(hjust = 0.5))

p2<- ggplot(mpg, aes(displ, hwy, colour = class)) + 
geom_point()+
theme(plot.caption = element_text(hjust = 0.5))

p3<- ggplot(mpg, aes(displ, hwy, colour = class)) + 
geom_point()+
theme(plot.caption = element_text(hjust = 0.5))

p4<- ggplot(mpg, aes(displ, hwy, colour = class)) + 
geom_point()+
theme(plot.caption = element_text(hjust = 0.5))

p1
p2
p3
p4
```

编辑

为确保子图之间有边距，您可以在加载包时添加margins选项：

  - \usepackage[margin = 8pt]{subfig}

查看包文档中的其他选项：http://anorien.csc.warwick.ac.uk/mirrors/CTAN/macros/latex/contrib/subfig/subfig.pdf