Hi all
I am trying to do some query on a graph. The graph contains subjects
with x and y values (separate statements) and I want to retrieve all
subjects within a certain distance of a point. This seems to work
according to the code below. However, I cannot pass the point (x0, y0
and d0) as a parameter because it is not in the bindings of the query.
How can this be achieved all the same?
Is it prefereable to use the new bison sparql implementation instead?
How would this look then?
def in_range(binding):
x0 = 100
y0 = 100
d0 = 25
dx = binding['?x'] - x0
dy = binding['?y'] - y0
d = math.sqrt(dx*dx + dy*dy)
if d <= d0:
return True
else:
return False
context = ConjunctiveGraph()
# fill graph with triples
sparqlGr = sparqlGraph.SPARQLGraph(graph=context)
select = ('?s', '?x', '?y')
where = GraphPattern([('?s', 'x', '?x'), ('?s', 'y', '?y')])
where.addConstraint(in_range)
result = sparqlGr.query(select, where)
thanks a lot for your help
Andre
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