transitive

An example illustrating how to use the Graph.transitive_subjects and Graph.transitive_objects graph methods

Formal definition

The Graph.transitive_objects method finds all nodes such that there is a path from subject to one of those nodes using only the predicate property in the triples. The Graph.transitive_subjects method is similar; it finds all nodes such that there is a path from the node to the object using only the predicate property.

Informal description, with an example

In brief, Graph.transitive_objects walks forward in a graph using a particular property, and Graph.transitive_subjects walks backward. A good example uses a property ex:parent, the semantics of which are biological parentage. The Graph.transitive_objects method would get all the ancestors of a particular person (all nodes such that there is a parent path between the person and the object). The Graph.transitive_subjects method would get all the descendants of a particular person (all nodes such that there is a parent path between the node and the person). So, say that your URI is ex:person.

This example would get all of your (known) ancestors, and then get all the (known) descendants of your maternal grandmother.

Important note on arguments

The Graph.transitive_objects method has the start node as the first argument, but the Graph.transitive_subjects method has the start node as the second argument.

User-defined transitive closures

The method Graph.transitiveClosure returns transtive closures of user-defined functions.

Attributes:

• dad –
• dadOfDad –
• dadOfMom –
• g –
• mom –
• momOfDad –
• momOfMom –
• parent –
• person –

dad module-attribute

dad = URIRef('ex:d')

dadOfDad module-attribute

dadOfDad = URIRef('ex:gf0')

dadOfMom module-attribute

dadOfMom = URIRef('ex:gf1')

g module-attribute

g = ConjunctiveGraph()

mom module-attribute

mom = URIRef('ex:m')

momOfDad module-attribute

momOfDad = URIRef('ex:gm0')

momOfMom module-attribute

momOfMom = URIRef('ex:gm1')

parent module-attribute

parent = URIRef('ex:parent')

person module-attribute

person = URIRef('ex:person')

_source: false show_docstring_attributes: false show_docstring_functions: false show_docstring_modules: false show_docstring_classes: false show_signature: false show_signature_annotations: false show_signature_type_parameters: false show_docstring_other_parameters: false show_docstring_parameters: false show_docstring_raises: false show_docstring_receives: false show_docstring_returns: false summary: false show_if_no_docstring: false

if __name__ == "__main__":
    from rdflib import ConjunctiveGraph, URIRef

    person = URIRef("ex:person")
    dad = URIRef("ex:d")
    mom = URIRef("ex:m")
    momOfDad = URIRef("ex:gm0")  # noqa: N816
    momOfMom = URIRef("ex:gm1")  # noqa: N816
    dadOfDad = URIRef("ex:gf0")  # noqa: N816
    dadOfMom = URIRef("ex:gf1")  # noqa: N816

    parent = URIRef("ex:parent")

    g = ConjunctiveGraph()
    g.add((person, parent, dad))
    g.add((person, parent, mom))
    g.add((dad, parent, momOfDad))
    g.add((dad, parent, dadOfDad))
    g.add((mom, parent, momOfMom))
    g.add((mom, parent, dadOfMom))

    print("Parents, forward from `ex:person`:")
    for i in g.transitive_objects(person, parent):
        print(i)

    print("Parents, *backward* from `ex:gm1`:")
    for i in g.transitive_subjects(parent, momOfMom):
        print(i)