Querying a vector of strings to Wikidata using WikidataQueryServiceR - r

Question

Provided a vector of movies' names, I would like to know their genres querying Wikidata.
Since I am a R user, I have recently discovered WikidataQueryServiceR which has exactly the same example I was looking for:
library(WikidataQueryServiceR)
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". }
}')
## 5 rows were returned by WDQS
Unfortunately, this query uses a static text, so I would like to replace The Cabin in the Woods by a vector. In order to do, I tried with the following code:
library(WikidataQueryServiceR)
example <- "The Cabin in the Woods" # Single string for testing purposes.
query_wikidata(paste('SELECT DISTINCT ?human ?humanLabel ?sex_or_gender ?sex_or_genderLabel WHERE {
?human wdt:P31 wd:Q5.
?human rdfs:label', example, '#en.
?human wdt:P21 ?sex_or_gender.
SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
OPTIONAL { ?human wdt:P2561 ?name. }
}', sep = ""))
But that does not work as expected, as I get the following result:
Error in FUN(X[[i]], ...) : Bad Request (HTTP 400).
What am I doing wrong?

Answer 1

Have you tried to output your SPARQL query? —
There is no space after rdfs:label
There are no quotes around The Cabin in the Woods
In your R code, instead of
?human rdfs:label', example, '#en.
line 7 should be:
?human rdfs:label "', example, '"#en.
Although query_wikidata() can accept vector of strings, I'd suggest to use SPARQL 1.1 VALUES instead, in order to avoid too many requests.
library(WikidataQueryServiceR)
example <- c("John Lennon", "Paul McCartney")
values <- paste(sprintf("('%s'#en)", example), collapse=" ")
query <- paste(
'SELECT DISTINCT ?label ?human ?humanLabel ?sexLabel {
VALUES(?label) {', values,
'}
?human wdt:P31 wd:Q5.
?human rdfs:label ?label.
?human wdt:P21 ?sex.
SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}'
)
query_wikidata(query)
For large number of VALUES, you probably need to use the development verion of WikidataQueryServiceR: it seems that only the development version supports POST requests.