问题
My Rmarkdown document looks something like this.
---
yaml metadata
---
```{r}
x <- 10
```
Some code explanation
```{r}
y <- 10
```
Some more code explanation
```{r}
z <- x + y
```
The final output
```
# 10
```
Since I am following the concepts of literate programming, how to print these multiple code chunks stitched together, so I can get the whole working code printed out as follows without the code explanation. Also, can I select specific code chunks and not all and print them out?
x <- 10
y <- 10
z <- x + y
回答1:
A trick is to use knitr's ref.label="" chunk option (which takes one or more block labels). It requires that you label your chunks (at least the ones you want to repeat). For demonstration, I've "hidden" (echo=FALSE) one of the blocks to show that the output can be offset (as in https://stackoverflow.com/a/30243074/3358272) though it is still executed in-place.
---
output: md_document
---
```{r block1}
x <- 10
```
Some code explanation, next code block hidden here but still evaluated
```{r block2, echo = FALSE}
y <- 10
```
Some more code explanation
```{r block3}
z <- x + y
```
The final output
```
# 10
```
# Annex 1
Each block individually:
```{r showblock1, ref.label='block1', eval=FALSE}
```
```{r showblock2, ref.label='block2', eval=FALSE}
```
```{r showblock3, ref.label='block3', eval=FALSE}
```
# Annex 2
If you want them more compactly concatenated:
```{r showblocks, ref.label=c('block1','block2','block3'), eval=FALSE}
Produces this markdown file when rendered:
x <- 10
Some code explanation, next code block hidden here but still evaluated
Some more code explanation
z <- x + y
The final output
# 10
Annex 1
=======
Each block individually:
x <- 10
y <- 10
z <- x + y
Annex 2
=======
If you want them more compactly concatenated:
x <- 10
y <- 10
z <- x + y
You can render into whatever format you want, the results should be similar.
来源：https://stackoverflow.com/questions/52952797/how-to-merge-and-print-multiple-code-chunks-in-rmarkdown