tests/testthat/examples/knitr-examples/094-purl-qmd.md

In parsermd: Formal Parser and Related Tools for R Markdown Documents

An example for purl()

The function purl() can be used to extract code chunks from a document.

1+1

## [1] 2

strsplit('hello world', ' ')

## [[1]]
## [1] "hello" "world"

A second chunk.

if (FALSE) plot(1:10)

When we do not evaluate a chunk, the code from purl() will be commented out.

paste(letters, collapse = '|')
if (1 == 1) {
  'Awesome!'
}

If one chunk should not be included in the results from purl(), just use the chunk option purl = FALSE:

# we do not like significance stars!
options(stringsAsFactors = FALSE, show.signif.stars = FALSE)

When a code chunk is supposed to error, use error = TRUE, and purl() will wrap the code in try():

1 + 'a'

## Error in `1 + "a"`:
## ! non-numeric argument to binary operator

That is it.

parsermd documentation built on Aug. 21, 2025, 5:27 p.m.