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% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/rdf_add.R
\name{rdf_add}
\alias{rdf_add}
\title{Add RDF Triples}
\usage{
rdf_add(
rdf,
subject,
predicate,
object,
subjectType = as.character(NA),
objectType = as.character(NA),
datatype_uri = as.character(NA)
)
}
\arguments{
\item{rdf}{an rdf object}
\item{subject}{character string containing the subject}
\item{predicate}{character string containing the predicate}
\item{object}{character string containing the object}
\item{subjectType}{the Node type of the subject, i.e. "uri", "blank"}
\item{objectType}{the Node type of the object, i.e. "literal", "uri", "blank"}
\item{datatype_uri}{the datatype URI to associate with a object literal value}
}
\value{
Silently returns the updated RDF graph (rdf object).
Since the rdf object simply contains external pointers
to the model object in C code, note that the input object is modified
directly, so you need not assign the output of rdf_add() to anything.
}
\description{
add a triple (subject, predicate, object) to the RDF graph
}
\details{
\code{rdf_add()} will automatically 'duck type' nodes (if looks like a duck...).
That is, strings that look like URIs will be declared as URIs. (See
\href{https://en.wikipedia.org/wiki/Uniform_Resource_Identifier}{URI}).
Predicate should always be a URI (e.g. URL or a \code{prefix:string}),
cannot be blank or literal. Subjects that look like strings will be
treated as \href{https://en.wikipedia.org/wiki/Blank_node}{Blank Nodes} (i.e.
will be prefixed with \verb{_:}). An empty subject, \code{""}, will create a
blank node with random name. Objects that look like URIs will be
typed as resource nodes, otherwise as literals. An empty object \code{""}
will be treated as blank node. Set \code{subjectType} or \code{objectType}
explicitly to override this behavior, e.g. to treat an object URI
as a literal string. NAs are also treated as blank nodes in subject
or object See examples for details.
}
\examples{
rdf <- rdf()
rdf_add(rdf,
subject="http://www.dajobe.org/",
predicate="http://purl.org/dc/elements/1.1/language",
object="en")
## non-URI string in subject indicates a blank subject
## (prefixes to "_:b0")
rdf_add(rdf, "b0", "http://schema.org/jobTitle", "Professor")
## identically a blank subject.
## Note rdf is unchanged when we add the same triple twice.
rdf_add(rdf, "b0", "http://schema.org/jobTitle", "Professor",
subjectType = "blank")
## blank node with empty string creates a default blank node id
rdf_add(rdf, "", "http://schema.org/jobTitle", "Professor")
## Subject and Object both recognized as URI resources:
rdf_add(rdf,
"https://orcid.org/0000-0002-1642-628X",
"http://schema.org/homepage",
"http://carlboettiger.info")
## Force object to be literal, not URI resource
rdf_add(rdf,
"https://orcid.org/0000-0002-1642-628X",
"http://schema.org/homepage",
"http://carlboettiger.info",
objectType = "literal")
}
\references{
\url{https://en.wikipedia.org/wiki/Uniform_Resource_Identifier}
}
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