The function all_labels() returns all chunk labels as a character
vector. Optionally, you can specify a series of conditions to filter the
labels. The function `all_rcpp_labels()` is a wrapper function for
all_labels(engine == 'Rcpp').
all_labels(...)
all_rcpp_labels(...)A vector of R expressions, each of which should return TRUE
or FALSE. The expressions are evaluated using the local chunk
options of each code chunk as the environment, which means global chunk
options are not considered when evaluating these expressions. For example,
if you set the global chunk option opts_chunk$set(purl = TRUE),
all_labels(purl == TRUE) will not return the labels of all
code chunks, but will only return the labels of those code chunks that have
local chunk options purl = TRUE.
A character vector.
For example, suppose the condition expression is engine == 'Rcpp', the
object engine is the local chunk option engine. If an
expression fails to be evaluated (e.g. when a certain object does not exist),
FALSE is returned and the label for this chunk will be filtered out.
Empty code chunks are always ignored, including those chunks that are
empty in the original document but filled with code using chunk options
such as ref.label or code.
# the examples below are meaningless unless you put them in a knitr document
all_labels()
#> NULL
all_labels(engine == "Rcpp")
#> NULL
all_labels(echo == FALSE && results != "hide")
#> NULL
# or separate the two conditions
all_labels(echo == FALSE, results != "hide")
#> NULL