rdflib

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("cboettig/rdflib")

Basic use

While not required, rdflib is designed to play nicely with %>% pipes, so we will load the magrittr package as well:

library(magrittr)
library(rdflib)

Parse a file and serialize into a different format:

doc <- system.file("extdata", "dc.rdf", package="redland")

doc %>%
  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 . }'

rdf <- rdf_parse(doc)
rdf
#> <http://www.dajobe.org/> <http://purl.org/dc/elements/1.1/description> "The generic home page of Dave Beckett." .
#> <http://www.dajobe.org/> <http://purl.org/dc/elements/1.1/title> "Dave Beckett's Home Page" .
#> <http://www.dajobe.org/> <http://purl.org/dc/elements/1.1/creator> "Dave Beckett" .


rdf %>% rdf_query(sparql)
#> # A tibble: 1 x 2
#>   a                      c           
#>   <chr>                  <chr>       
#> 1 http://www.dajobe.org/ Dave Beckett

Initialize 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
#> <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
#> {
#>   "@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")
#> {
#>   "@id": "http://www.dajobe.org/",
#>   "http://purl.org/dc/elements/1.1/language": "en"
#> }

For more information on the JSON-LD RDF API, see https://json-ld.org/spec/latest/json-ld-rdf/.

---

Citing rdflib

citation("rdflib")
#> Warning in citation("rdflib"): no date field in DESCRIPTION file of package
#> 'rdflib'
#> Warning in citation("rdflib"): could not determine year for 'rdflib' from
#> package DESCRIPTION file

To cite package 'rdflib' in publications use:

Carl Boettiger (NA). rdflib: Tools to Manipulate and Query Semantic Data. R package version 0.0.4. https://github.com/cboettig/rdflib

A BibTeX entry for LaTeX users is

@Manual{, title = {rdflib: Tools to Manipulate and Query Semantic Data}, author = {Carl Boettiger}, note = {R package version 0.0.4}, url = {https://github.com/cboettig/rdflib}, }

Please also cite the underlying redland library:

citation("redland")

Jones M, Slaughter P, Ooms J, Boettiger C and Chamberlain S (2016). redland: RDF Library Bindings in R. doi: 10.5063/F1VM496B (URL: http://doi.org/10.5063/F1VM496B), R package version 1.0.17-9, <URL: https://github.com/ropensci/redland-bindings/tree/master/R/redland>.

A BibTeX entry for LaTeX users is

@Manual{, title = {{redland}: RDF Library Bindings in R}, author = {Matthew B. Jones and Peter Slaughter and Jeroen Ooms and Carl Boettiger and Scott Chamberlain}, year = {2016}, note = {R package version 1.0.17-9}, url = {https://github.com/ropensci/redland-bindings/tree/master/R/redland}, doi = {10.5063/F1VM496B}, }