purl() within knit() duplicate label error

Question

I am knitting a .Rmd file and want to have two outputs: the html and a purl\'ed R script each time I run knit. This can be done with the following Rmd file:

---         


        

Answer 1

You can allow duplicate labels by including options(knitr.duplicate.label = 'allow') within the file as follows:

title: "Purl MWE"
output: html_document
---

```{r GlobalOptions}
options(knitr.duplicate.label = 'allow')
```


```{r}
## This chunk automatically generates a text .R version of this script when     running within knitr.
input  = knitr::current_input()  # filename of input document
output = paste(tools::file_path_sans_ext(input), 'R', sep = '.')
knitr::purl(input,output,documentation=1,quiet=T)
```


```{r test}
x=1
x
```

This code isn't documented on the knitr website, but you can keep track with the latest changes direct from Github: https://github.com/yihui/knitr/blob/master/NEWS.md