README.md

In WikidataQueryServiceR: API Client Library for 'Wikidata Query Service'

WikidataQueryServiceR

• Installation
• Usage
  • Example: fetching genres of a particular movie
  • Fetching queries from Wikidata’s examples page
• Links for learning SPARQL
• Additional Information

This is an R wrapper for the Wikidata Query Service (WDQS) which provides a way for tools to query Wikidata via SPARQL (see the beta at https://query.wikidata.org/). It is written in and for R, and was inspired by Os Keyes’ WikipediR and WikidataR packages.

Author: Mikhail Popov (Wikimedia Foundation) License: MIT Status: Active

Installation

install.packages("WikidataQueryServiceR")

To install the development version:

# install.packages("remotes")
remotes::install_github("bearloga/WikidataQueryServiceR")

Usage

library(WikidataQueryServiceR)

## See ?WDQS for resources on Wikidata Query Service and SPARQL

You submit SPARQL queries using the query_wikidata() function.

Example: fetching genres of a particular movie

In this example, we find an “instance of” (P31) “film” (Q11424) that has the label “The Cabin in the Woods” (Q45394), get its genres (P136), and then use WDQS label service to return the genre labels.

query_wikidata('SELECT DISTINCT
  ?genre ?genreLabel
WHERE {
  ?film wdt:P31 wd:Q11424.
  ?film rdfs:label "The Cabin in the Woods"@en.
  ?film wdt:P136 ?genre.
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}')

| genre | genreLabel | | :---------------------------------------- | :------------------- | | http://www.wikidata.org/entity/Q3072049 | zombie film | | http://www.wikidata.org/entity/Q471839 | science fiction film | | http://www.wikidata.org/entity/Q859369 | comedy-drama | | http://www.wikidata.org/entity/Q1342372 | monster film | | http://www.wikidata.org/entity/Q853630 | slasher film | | http://www.wikidata.org/entity/Q224700 | comedy horror |

For more example SPARQL queries, see this page on Wikidata.

query_wikidata() can accept multiple queries, returning a (potentially named) list of data frames. If the vector of SPARQL queries is named, the results will inherit those names.

Fetching queries from Wikidata’s examples page

The package provides a WikipediR-based function for getting SPARQL queries from the WDQS examples page.

sparql_query <- get_example(c("Cats", "How many states this US state borders"))

sparql_query[["How many states this US state borders"]]

 #added before 2016-10
SELECT ?state ?stateLabel ?borders
WHERE
{
  {
    SELECT ?state (COUNT(?otherState) as ?borders)
    WHERE
    {
    ?state wdt:P31 wd:Q35657 .
    ?otherState wdt:P47 ?state .
    ?otherState wdt:P31 wd:Q35657 .
    }
    GROUP BY ?state
  }
  SERVICE wikibase:label {
    bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en" .
  }
}        
ORDER BY DESC(?borders) 

Now we can run all extracted SPARQL queries:

results <- query_wikidata(sparql_query)
lapply(results, dim)

## $Cats
## [1] 147   2
## 
## $`How many states this US state borders`
## [1] 48  3

head(results$`How many states this US state borders`)

| state | stateLabel | borders | | :------------------------------------- | :----------- | ------: | | http://www.wikidata.org/entity/Q1509 | Tennessee | 8 | | http://www.wikidata.org/entity/Q1581 | Missouri | 8 | | http://www.wikidata.org/entity/Q1261 | Colorado | 7 | | http://www.wikidata.org/entity/Q1603 | Kentucky | 7 | | http://www.wikidata.org/entity/Q1400 | Pennsylvania | 6 | | http://www.wikidata.org/entity/Q1211 | South Dakota | 6 |

Links for learning SPARQL

• A beginner-friendly course for SPARQL
• Building a SPARQL query: Museums on Instagram
• SPARQL Query Examples for WDQS
• Using SPARQL to access Linked Open Data by Matthew Lincoln
• Interesting or illustrative SPARQL queries for Wikidata
• Wikidata 2016 SPARQL Workshop
• Wikidata SPARQL Query video tutorial by Navino Evans
• Learning SPARQL by Bob DuCharme
• WDQS User Manual

Additional Information

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.

WikidataQueryServiceR documentation built on July 2, 2020, 2:12 a.m.