python - 如何在 RDFLib 中为图形添加注释或标签？

Question

我正在尝试将数据集的名称添加到图形对象并稍后检索它们，很确定必须有简单的方法来完成它，但到目前为止找不到任何东西......谢谢

Answer 1

我认为您正在寻找的是将上下文附加到图形。这就像创建一个图来解析其中的子图，每个子图都有一个名称 - 如果是 rdflib，则为 URIRef。

假设您必须使用以下两个文件表示图表:

数据A.nt

<http://data.org/inst1> <http://xmlns.com/foaf/0.1/name> "david" .
<http://data.org/inst2> <http://xmlns.com/foaf/0.1/name> "luis" .
<http://data.org/inst3> <http://xmlns.com/foaf/0.1/name> "max" .

数据B.nt

<http://data.org/inst1> <http://xmlns.com/foaf/0.1/knows> <http://data.org/inst2> .
<http://data.org/inst2> <http://xmlns.com/foaf/0.1/knows> <http://data.org/inst3> .
<http://data.org/inst3> <http://xmlns.com/foaf/0.1/knows> <http://data.org/inst1> .

还有下面的一段代码:

import rdflib

g = rdflib.ConjunctiveGraph("IOMemory",)

#g is made of two sub-graphs or triples gathered in two different contexts.
#the second paramaters identifies the URIRef for each subgraph.
g.parse("dataA.nt",rdflib.URIRef("http://mygraphs.org/names"),format="n3")
g.parse("dataB.nt",rdflib.URIRef("http://mygraphs.org/relations"),format="n3")

print "traverse all contexts and all triples for each context"
for subgraph in g.contexts():
    print "Graph name",subgraph.identifier 
    for triple in subgraph.triples((None,None,None)):
        print triple

print "traverse all contexts where a triple appears"
for subgraph in g.contexts(triple=(rdflib.URIRef('http://data.org/inst1'),rdflib.URIRef("http://xmlns.com/foaf/0.1/name"),rdflib.Literal(u'david'))):
    print "Graph name",subgraph.identifier 
    for triple in subgraph.triples((None,None,None)):
        print triple

print "traverse a triple pattern regardless the context is in"
for t in g.triples((None,rdflib.URIRef("http://xmlns.com/foaf/0.1/name"),None)):
    print t