如何从 RMarkdown (.Rmd) 文件中提取所有代码？

Question

如何从 RMarkdown (.Rmd) 文件中提取所有代码（块）并将它们转储到纯 R 脚本中？

基本上我想做这个问题中描述的补充操作，它使用块选项来提取 Rmd 的文本（即非代码）部分。

所以具体来说我想从一个 Rmd 文件开始，如下所示

---
title: "My RMarkdown Report"
author: "John Appleseed"
date: "19/02/2022"
output: html_document
---

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

## R Markdown

Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents.   
For more details on using R Markdown see <http://rmarkdown.rstudio.com>.  

Some text description here. 

```{r cars}
a = 1
print(a)
summary(cars)
```

## Including Plots

You can also embed plots, for example:

```{r pressure, echo=FALSE}
plot(pressure)
```

Some more comments here.

对于仅包含上述代码部分的 R 脚本，如下所示：

---
title: "My RMarkdown Report"
author: "John Appleseed"
date: "19/02/2022"
output: html_document
---

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

## R Markdown

Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents.   
For more details on using R Markdown see <http://rmarkdown.rstudio.com>.  

Some text description here. 

```{r cars}
a = 1
print(a)
summary(cars)
```

## Including Plots

You can also embed plots, for example:

```{r pressure, echo=FALSE}
plot(pressure)
```

Some more comments here.

Answer 1

您可以使用knitr::purl，请参阅将 Markdown 转换为 R 脚本：

knitr::purl(input = "Report.Rmd", output = "Report.R",documentation = 0)

给出Report.R：

knitr::opts_chunk$set(echo = TRUE)

a = 1
print(a)
summary(cars)

plot(pressure)

Answer 2

另一种方法是将purl钩子设置在您的Rmd：

```{r setup, include=FALSE}
knitr::knit_hooks$set(purl = knitr::hook_purl)
knitr::opts_chunk$set(echo = TRUE)
```

然后在编织时会生成 R 脚本。您可以使用 chunk 选项排除一些块purl = FALSE。