Method add_edge

pattern/graph/__init__.py:362–385

Appends a new Edge to the graph. An optional base parameter can be used to pass a subclass of Edge: Graph.add_edge("cold", "winter", base=IsPropertyOf)

(self, id1, id2, *args, **kwargs)

        return n
    
    def add_edge(self, id1, id2, *args, **kwargs):
        """ Appends a new Edge to the graph.
            An optional base parameter can be used to pass a subclass of Edge:
            Graph.add_edge("cold", "winter", base=IsPropertyOf)
        """
        # Create nodes that are not yet part of the graph.
        n1 = self.add_node(id1)
        n2 = self.add_node(id2)
        # Creates an Edge instance.
        # If an edge (in the same direction) already exists, yields that edge instead.
        e1 = n1.links.edge(n2)
        if e1 and e1.node1 == n1 and e1.node2 == n2:
            return e1
        e2 = kwargs.pop("base", Edge)
        e2 = e2(n1, n2, *args, **kwargs)
        self.edges.append(e2)
        # Synchronizes Node.links:
        # A.links.edge(B) yields edge A->B
        # B.links.edge(A) yields edge B->A
        n1.links.append(n2, edge=e2)
        n2.links.append(n1, edge=e1 or e2)
        # Clear adjacency cache.
        self._adjacency = None
        return e2        
            
    def remove(self, x):
        """ Removes the given Node (and all its edges) or Edge from the graph.