rdflib 查询 sparql 导致使用 FILTER 键解析错误

Question

我正在尝试运行使用 rdflib 对图进行 SPARQL 查询。如果我不使用 FILTER，它会很好地工作，否则它会导致在将字符串解析为查询时出错。 我正在使用 PYTHON 2.7。查看其他人的查询，我看不到任何语法错误。这里查询：

 query = " SELECT ?textspan WHERE " \
             " { ?textspan rst:startOffset ?start ; " \
             "                    rst:endOffset ?end . " \
             "    FILTER ( ?start <= "+denotedStartOffset+" < ?end ) } "

他们与：

 query = " SELECT ?textspan WHERE " \
             " { ?textspan rst:startOffset ?start ; " \
             "                    rst:endOffset ?end . " \
             "    FILTER ( ?start <= 5 < ?end ) } "

错误：

Traceback (most recent call last):
  File "link.py", line 27, in <module>
    qres = g.query(QUERY_2)
  File "/usr/local/lib/python2.7/dist-packages/rdflib/graph.py", line 1085, in query
    query_object, initBindings, initNs, **kwargs))
  File "/usr/local/lib/python2.7/dist-packages/rdflib/plugins/sparql/processor.py", line 74, in query
    parsetree = parseQuery(strOrQuery)
  File "/usr/local/lib/python2.7/dist-packages/rdflib/plugins/sparql/parser.py", line 1058, in parseQuery
    return Query.parseString(q, parseAll=True)
  File "/usr/local/lib/python2.7/dist-packages/pyparsing.py", line 1947, in parseString
    raise exc
pyparsing.ParseException: Expected {SelectQuery | ConstructQuery | DescribeQuery | AskQuery}, found u'F'  (at char 103), (line:1, col:104)

它说它不期望 'F' 所以它不识别 FILTER。

Answer 1

正如@UninformedUser 建议的那样，解决方案是 FILTER ( ?start <= 5 && 5 < ?end )

rdflib 查询 sparql 导致使用 FILTER 键解析错误

rdflib query sparql cause parsing error with FILTER key

filter

sparql

querying

rdflib