A friendly and consise user interface for performing common tasks on rdf data, such as parsing and converting between formats including rdfxml, turtle, nquads, ntriples, and trig, creating rdf graphs, and performing SPARQL queries. This package wraps the redland R package which provides direct bindings to the redland C library. Additionally, the package supports parsing and serialization of rdf into json-ld through the json-ld package, which binds the official json-ld javascript API. The package interface takes inspiration from the Python rdflib library.
Installation
You can install rdflib from GitHub with:
# install.packages("devtools")devtools::install_github("ropensci/rdflib")Basic use
While not required,rdflib is designed to play nicely with%>% pipes, so we will load themagrittr package as well:
Parse a file and serialize into a different format:
system.file("extdata/dc.rdf", package="redland")%>%rdf_parse()%>%rdf_serialize("test.nquads","nquads")Perform SPARQL queries:
sparql<-'PREFIX dc: <http://purl.org/dc/elements/1.1/> SELECT ?a ?c WHERE { ?a dc:creator ?c . }'system.file("extdata/dc.rdf", package="redland")%>%rdf_parse()%>%rdf_query(sparql)#> # A tibble: 1 × 2#> a c#> <chr> <chr>#> 1 http://www.dajobe.org/ Dave BeckettInitialize graph a new object or add triples statements to an existing graph:
x<-rdf()x<-rdf_add(x, subject="http://www.dajobe.org/", predicate="http://purl.org/dc/elements/1.1/language", object="en")x#> Total of 1 triples, stored in hashes#> -------------------------------#> <http://www.dajobe.org/> <http://purl.org/dc/elements/1.1/language> "en" .Change the default display format (nquads) for graph objects:
options(rdf_print_format="jsonld")x#> Total of 1 triples, stored in hashes#> -------------------------------#> {#> "@id": "http://www.dajobe.org/",#> "http://purl.org/dc/elements/1.1/language": "en"#> }JSON-LD
We can also work with the JSON-LD format through additional functions provided in the R package,jsonld.
out<-tempfile()rdf_serialize(x,out,"jsonld")rdf_parse(out, format="jsonld")#> Total of 1 triples, stored in hashes#> -------------------------------#> {#> "@id": "http://www.dajobe.org/",#> "http://purl.org/dc/elements/1.1/language": "en"#> }For more information on the JSON-LD RDF API, seehttps://json-ld.org/spec/latest/json-ld-rdf/.
Advanced Use
Seearticles from the documentation for advanced use including applications to large triplestores, example SPARQL queries, and information about additional database backends.
Citing rdflib
Please also cite the underlyingredland library when citingrdflib
Carl Boettiger. (2018). rdflib: A high level wrapper around the redland package for common rdf applications (Version 0.1.0). Zenodo.https://doi.org/10.5281/zenodo.1098478
Jones M, Slaughter P, Ooms J, Boettiger C, Chamberlain S (2022).redland: RDF Library Bindings in R.doi:10.5063/F1VM496Bhttps://doi.org/10.5063/F1VM496B, R package version 1.0.17-16,https://github.com/ropensci/redland-bindings/tree/master/R/redland.
