all_labels.Rd

% Please edit documentation in R/parser.R
\name{all_labels}
\alias{all_labels}
\title{Get all chunk labels in a document}
\usage{
all_labels(...)
}
\arguments{
\item{...}{a series of R expressions, each of which should return \code{TRUE}
or \code{FALSE}; the expressions are evaluated using the local chunk
options of each code chunk as the environment}
}
\value{
A character vector.
}
\description{
This function returns all chunk labels as a chracter vector. Optionally, you
can specify a series of conditions to filter the labels.
}
\details{
For example, suppose the condition expression is \code{engine == 'Rcpp'}, the
object \code{engine} is the local chunk option \code{engine}; if an
expression fails to be evaluated (e.g. when a certain object does not exist),
\code{FALSE} is returned and the label for this chunk will be filtered out.
}
\note{
Empty code chunks are always ignored, including those chunks that are
  empty originally in the document but filled with code using chunk options
  such as \code{ref.label} or \code{code}.
}
\examples{
# the examples below are meaningless unless you put them in a knitr document
all_labels()
all_labels(engine == "Rcpp")
all_labels(echo == FALSE && results != "hide")
# or separate the two conditions
all_labels(echo == FALSE, results != "hide")
}