如何使用Knitr在代码块内的子图之间插入分页符 [英] How to insert page break among subfigures inside a code chunk with knitr

问题描述

我有以下R arkdown代码:

I have the following R arkdown code:

---
output:
  pdf_document: default
  keep_tex: yes
header-includes: 
  - \usepackage{subfig}
---


```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = F)
library(ggplot2)
library(knitr)
```
## Including Plots

You can also embed plots, for example:
```{r pressure, echo=FALSE, fig.width = 20, fig.height=10, fig.cap=LETTERS[1:3], fig.subcap=LETTERS[1:5], fig.ncol=2,  out.width='0.4\\linewidth'}
for (x in 1:3) {
  df <- data.frame(a = runif(50))
  p <- ggplot(df, aes(x=a)) + geom_histogram(bins=10)
  print(p)
  df <- data.frame(a = runif(50))
  p <- ggplot(df, aes(x=a)) + geom_histogram(bins=10)
  print(p)
  df <- data.frame(a = runif(50))
  p <- ggplot(df, aes(x=a)) + geom_histogram(bins=10)
  print(p)
  df <- data.frame(a = runif(50))
  p <- ggplot(df, aes(x=a)) + geom_histogram(bins=10)
  print(p)
  df <- data.frame(a = runif(50))
  p <- ggplot(df, aes(x=a)) + geom_histogram(bins=10)
  print(p)
  cat('\n\\pagebreak\n')
}

我想要三个不同的图形，每个图形包含五个子图.我试图在第五个子图上打破这个数字，但这是行不通的.

I'd like to have three different figures, each containing five subfigures. I try to break the figure at the fifth subfigure, but it does not work.

推荐答案

fig.cap旨在采用单个参数，因此，我们将不得不以编程方式为所需的三个图分别生成新的代码块.如

fig.cap is designed to take a single argument, and therefore we are going to have to programmatically generate new code chunks for each of the three plots you want. As explained here, we can use the knit_expand function. I have amended the example provided to include the subfigure captions, and a way to print plots from a list.

我已经编写了函数splitSubFig，该函数将限制每个图的子图数量.如果我们超过这个数字，它将创建一个新页面.注意，您将需要在块标题中使用results="asis"来创建图形:

I have written the function splitSubFig which will limit the number of subfigures per plot. If we go over this number, it will create a new page. Note, you will need to use the results="asis" in the chunk header creating the figures:

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


```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = F)

library(ggplot2)
library(knitr)

# Function to create a separate chunk to generate a plot for each item in list
splitSubFig <- function(plots, caption, maxlength) {

  knitr::opts_knit$set(progress = FALSE, verbose = FALSE)

  n <- length(plots)
  numPages <- ceiling(n / maxlength)
  splitPlots <- split(plots, rep(1:ceiling(n/maxlength), each=maxlength)[1:n])

  for (page in 1:numPages) {

    cat(
      knit(text=knit_expand(
        text=(
          "```{r {{caption}}{{page}}, fig.cap='{{caption}}: {{page}}', fig.subcap=LETTERS[1:length(splitPlots[page])],  out.width='8cm', fig.ncol=2, echo = FALSE, message = FALSE}
for(i in splitPlots[page]){

for(plots in i){
 print(plots)
}

}
```"),
caption = caption,
page = LETTERS[page])))
  }
}

```

```{r, results="asis"}

plots <- list(ggplot(data.frame(a = runif(50)), aes(x=a)) + geom_histogram(bins=10, fill = "red"),
             ggplot(data.frame(a = runif(50)), aes(x=a)) + geom_histogram(bins=10),
             ggplot(data.frame(a = runif(50)), aes(x=a)) + geom_histogram(bins=10),
             ggplot(data.frame(a = runif(50)), aes(x=a)) + geom_histogram(bins=10),
             ggplot(data.frame(a = runif(50)), aes(x=a)) + geom_histogram(bins=10),
             ggplot(data.frame(a = runif(50)), aes(x=a)) + geom_histogram(bins=10, fill = "blue"),
             ggplot(data.frame(a = runif(50)), aes(x=a)) + geom_histogram(bins=10),
             ggplot(data.frame(a = runif(50)), aes(x=a)) + geom_histogram(bins=10),
             ggplot(data.frame(a = runif(50)), aes(x=a)) + geom_histogram(bins=10),
             ggplot(data.frame(a = runif(50)), aes(x=a)) + geom_histogram(bins=10))

splitSubFig(plots, caption = "Your Caption", maxlength = 6)
```

当然可以改进此功能，但是它应该可以满足您的需求！

This function could certainly be improved, but it should be good for what you need!

这篇关于如何使用Knitr在代码块内的子图之间插入分页符的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！