1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
|
"""
RDFLib can map between RDF data-typed literals and Python objects.
Mapping for integers, floats, dateTimes, etc. are already added, but
you can also add your own.
This example shows how :meth:`rdflib.term.bind` lets you register new
mappings between literal datatypes and Python objects
"""
from rdflib import XSD, Graph, Literal, Namespace, term
if __name__ == "__main__":
# Complex numbers are not registered by default
# No custom constructor/serializer needed since
# complex('(2+3j)') works fine
term.bind(XSD.complexNumber, complex)
# Create a complex number RDFlib Literal
EG = Namespace("http://example.com/")
c = complex(2, 3)
l = Literal(c)
# Add it to a graph
g = Graph()
g.add((EG.mysubject, EG.myprop, l))
# Print the triple to see what it looks like
print(list(g)[0])
# prints: (
# rdflib.term.URIRef('http://example.com/mysubject'),
# rdflib.term.URIRef('http://example.com/myprop'),
# rdflib.term.Literal(
# '(2+3j)',
# datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#complexNumber')
# )
# )
# Round-trip through n3 serialize/parse
g2 = Graph().parse(data=g.serialize())
l2 = list(g2)[0]
print(l2)
# Compare with the original python complex object (should be True)
# l2[2] is the object of the triple
assert isinstance(l2[2], Literal)
print(l2[2].value == c)
|
