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\name{[.XMLNode}
\alias{[.XMLNode}
\alias{[[.XMLNode}
\alias{[[.XMLInternalElementNode}
\alias{[[.XMLDocumentContent}
\title{Convenience accessors for the children of XMLNode objects.}
\description{
These provide a simplified syntax for extracting the children
of an XML node.
}
\usage{
\method{[}{XMLNode}(x, ..., all = FALSE)
\method{[[}{XMLNode}(x, ...)
\method{[[}{XMLDocumentContent}(x, ...)
}
\arguments{
\item{x}{the XML node or the top-level document content in which the children are to be accessed.
The \code{XMLDocumentContent} is the container for the top-level node that also contains information
such as the URI/filename and XML version. This accessor method is merely a convenience to get
access to children of the top-level node.}
% \item{i}{index of the child of interest or the name of an XML element
% of interest. In this latter case, only the first matching element is
% returned, if any.}
\item{\dots}{the identifiers for the children to be retrieved,
given as integer indices, names, etc. in the usual format for the
generic \code{link{[}} and \code{link{[[}} operators}
\item{all}{logical value. When \dots is a character vector, a value
of \code{TRUE} for \code{all} means to retrieve all of the
nodes with those names rather than just the first one.
\code{FALSE} gives the usual result of subsetting a list by name
which gives just the first element.
This allows us to avoid the idiom
\code{node[ names(node) == "bob" ]}
which is complicated when node is the result of an inline
computation
and instead we use
\code{node["bob", all = TRUE]}.
}
}
\value{
A list or single element containing the
children of the XML node given by \code{obj}
and identified by \dots.
}
\references{\url{https://www.w3.org/XML/}, \url{https://www.omegahat.net/RSXML/}}
\author{Duncan Temple Lang}
\seealso{
\code{\link{xmlAttrs}}
\code{\link{[<-.XMLNode}}
\code{\link{[[<-.XMLNode}}
}
\examples{
f = system.file("exampleData", "gnumeric.xml", package = "XML")
top = xmlRoot(xmlTreeParse(f))
# Get the first RowInfo element.
top[["Sheets"]][[1]][["Rows"]][["RowInfo"]]
# Get a list containing only the first row element
top[["Sheets"]][[1]][["Rows"]]["RowInfo"]
top[["Sheets"]][[1]][["Rows"]][1]
# Get all of the RowInfo elements by position
top[["Sheets"]][[1]][["Rows"]][1:xmlSize(top[["Sheets"]][[1]][["Rows"]])]
# But more succinctly and accurately, get all of the RowInfo elements
top[["Sheets"]][[1]][["Rows"]]["RowInfo", all = TRUE]
}
\keyword{IO}
\keyword{file}
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