Method to_directed

easygraph/classes/multigraph.py:620–671

Returns a directed representation of the graph. Returns ------- G : MultiDiGraph A directed graph with the same name, same nodes, and with each edge (u, v, data) replaced by two directed edges (u, v, data) and (v, u, data). Notes

(self)

        return G

    def to_directed(self):
        """Returns a directed representation of the graph.

        Returns
        -------
        G : MultiDiGraph
            A directed graph with the same name, same nodes, and with
            each edge (u, v, data) replaced by two directed edges
            (u, v, data) and (v, u, data).

        Notes
        -----
        This returns a "deepcopy" of the edge, node, and
        graph attributes which attempts to completely copy
        all of the data and references.

        This is in contrast to the similar D=DiGraph(G) which returns a
        shallow copy of the data.

        See the Python copy module for more information on shallow
        and deep copies, https://docs.python.org/3/library/copy.html.

        Warning: If you have subclassed MultiGraph to use dict-like objects
        in the data structure, those changes do not transfer to the
        MultiDiGraph created by this method.

        Examples
        --------
        >>> G = eg.Graph()  # or MultiGraph, etc
        >>> G.add_edge(0, 1)
        >>> H = G.to_directed()
        >>> list(H.edges)
        [(0, 1), (1, 0)]

        If already directed, return a (deep) copy

        >>> G = eg.DiGraph()  # or MultiDiGraph, etc
        >>> G.add_edge(0, 1)
        >>> H = G.to_directed()
        >>> list(H.edges)
        [(0, 1)]
        """
        G = eg.MultiDiGraph()
        G.graph.update(deepcopy(self.graph))
        G.add_nodes_from((n, deepcopy(d)) for n, d in self._node.items())
        G.add_edges_from(
            (u, v, key, deepcopy(datadict))
            for u, nbrs in self.adj.items()
            for v, keydict in nbrs.items()
            for key, datadict in keydict.items()
        )
        return G

    def number_of_edges(self, u=None, v=None):
        """Returns the number of edges between two nodes.