我可以在查询中包含URI和变量,但不能在查询中包含文字。
在这里,我有一些代码可以成功读取RDF文件,使用skos:prefLabels查找所有RDF三元组,对它们进行计数,然后从一组关键字中识别出几个特定的三元组:
import rdflib.plugins.sparql as sparql
import rdflib
import rdflib.graph as g
graph = g.Graph()
# Read the RDF file
graph.parse(
'h:\......SKOSTaxonomy.rdf',
format='xml')
# Build and execute the query
q = sparql.prepareQuery('SELECT ?s ?p ?o WHERE { ?s ?p ?o .}')
p = rdflib.URIRef("http://www.w3.org/2004/02/skos/core#prefLabel")
qres = graph.query(q, initBindings = {'p' : p})
print len(qres)
# Look for keywords among the results
keywords = set([u'Jackknifing', 'Technology-mapping', 'Something random'])
for (subj, pred, obj) in qres:
if obj.value in keywords:
print obj.value
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如预期的那样,此代码将输出: …