Module rdflib.Graph

>>> g=Graph()
>>> g.store.__class__
<class 'rdflib.store.IOMemory.IOMemory'>

>>> g.identifier.__class__
<class 'rdflib.BNode.BNode'>

Instanciating Graphs with a specific kind of store (IOMemory) and a default identifier (a BNode):

>>> store = plugin.get('IOMemory',Store)()
>>> store.__class__.__name__
'IOMemory'

>>> graph = Graph(store)
>>> graph.store.__class__
<class 'rdflib.store.IOMemory.IOMemory'>

>>> g=Graph('Sleepycat',URIRef("http://rdflib.net"))
>>> g.identifier
rdflib.URIRef('http://rdflib.net')

>>> str(g)
"<http://rdflib.net> a rdfg:Graph;rdflib:storage [a rdflib:Store;rdfs:label 'Sleepycat']."

>>> g=ConjunctiveGraph()
>>> str(g.default_context)
"[a rdfg:Graph;rdflib:storage [a rdflib:Store;rdfs:label 'IOMemory']]."

>>> g=Graph('IOMemory')
>>> statementId = BNode()
>>> print len(g)
0

>>> g.add((statementId,RDF.type,RDF.Statement))
>>> g.add((statementId,RDF.subject,URIRef('http://rdflib.net/store/ConjunctiveGraph')))
>>> g.add((statementId,RDF.predicate,RDFS.label))
>>> g.add((statementId,RDF.object,Literal("Conjunctive Graph")))
>>> print len(g)
4

>>> for s,p,o in g:  print type(s)
...

<class 'rdflib.BNode.BNode'>
<class 'rdflib.BNode.BNode'>
<class 'rdflib.BNode.BNode'>
<class 'rdflib.BNode.BNode'>

>>> for s,p,o in g.triples((None,RDF.object,None)):  print o
...

Conjunctive Graph

>>> g.remove((statementId,RDF.type,RDF.Statement))
>>> print len(g)
3

None terms in calls to triple can be thought of as 'open variables'

>>> store = plugin.get('IOMemory',Store)()
>>> g1 = Graph(store)
>>> g2 = Graph(store)
>>> g3 = Graph(store)
>>> stmt1 = BNode()
>>> stmt2 = BNode()
>>> stmt3 = BNode()
>>> g1.add((stmt1,RDF.type,RDF.Statement))
>>> g1.add((stmt1,RDF.subject,URIRef('http://rdflib.net/store/ConjunctiveGraph')))
>>> g1.add((stmt1,RDF.predicate,RDFS.label))
>>> g1.add((stmt1,RDF.object,Literal("Conjunctive Graph")))
>>> g2.add((stmt2,RDF.type,RDF.Statement))
>>> g2.add((stmt2,RDF.subject,URIRef('http://rdflib.net/store/ConjunctiveGraph')))
>>> g2.add((stmt2,RDF.predicate,RDF.type))
>>> g2.add((stmt2,RDF.object,RDFS.Class))
>>> g3.add((stmt3,RDF.type,RDF.Statement))
>>> g3.add((stmt3,RDF.subject,URIRef('http://rdflib.net/store/ConjunctiveGraph')))
>>> g3.add((stmt3,RDF.predicate,RDFS.comment))
>>> g3.add((stmt3,RDF.object,Literal("The top-level aggregate graph - The sum of all named graphs within a Store")))
>>> len(list(ConjunctiveGraph(store).subjects(RDF.type,RDF.Statement)))
3

>>> len(list(ReadOnlyGraphAggregate([g1,g2]).subjects(RDF.type,RDF.Statement)))
2

>>> from sets import Set    
>>> uniqueGraphNames = Set([graph.identifier for s,p,o,graph in ConjunctiveGraph(store).quads((None,RDF.predicate,None))])
>>> len(uniqueGraphNames)
3

>>> unionGraph = ReadOnlyGraphAggregate([g1,g2])
>>> uniqueGraphNames = Set([graph.identifier for s,p,o,graph in unionGraph.quads((None,RDF.predicate,None))])
>>> len(uniqueGraphNames)
2

>>> g2=Graph()
>>> src = """
... @prefix rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
... @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
... [ a rdf:Statement ;
...   rdf:subject <http://rdflib.net/store#ConjunctiveGraph>;
...   rdf:predicate rdfs:label;
...   rdf:object "Conjunctive Graph" ] """
>>> g2=g2.parse(StringIO(src),format='n3')
>>> print len(g2)
4

>>> RDFLib = Namespace('http://rdflib.net')
>>> RDFLib.ConjunctiveGraph
rdflib.URIRef('http://rdflib.netConjunctiveGraph')

>>> RDFLib['Graph']
rdflib.URIRef('http://rdflib.netGraph')

>>> print len(g)
3

>>> q = '''
... PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> SELECT ?pred WHERE { ?stmt rdf:predicate ?pred. }
... '''   
>>> for pred in g.query(q):  print pred
(rdflib.URIRef('http://www.w3.org/2000/01/rdf-schema#label'),)

>>> nsMap = {u"rdf":RDF.RDFNS}
>>> for pred in g.query("SELECT ?pred WHERE { ?stmt rdf:predicate ?pred. }", initNs=nsMap): print pred
(rdflib.URIRef('http://www.w3.org/2000/01/rdf-schema#label'),)

>>> top = { Variable("?term") : RDF.predicate }
>>> for pred in g.query("SELECT ?pred WHERE { ?stmt ?term ?pred. }", initBindings=top): print pred
(rdflib.URIRef('http://www.w3.org/2000/01/rdf-schema#label'),)