Method __setitem__

recipes/Python/578615_graph/recipe-578615.py:516–532

Set graph[vid] to VertexType(value). >>> g = Graph(VertexType=WVertex) >>> g[1] = {} #set g[1] to empty vertex (no out edges) >>> type(g[1]) is WVertex True >>> g[2] = {1: 4, 3: 9} #non-existent vertex values get created automatically >>> print g

(self, vid, value)

        return self.setdefault(vid, {}) #will convert plain {} to VertexType if necessary

    def __setitem__(self, vid, value):
        """Set graph[vid] to VertexType(value).

        >>> g = Graph(VertexType=WVertex)
        >>> g[1] = {}  #set g[1] to empty vertex (no out edges)
        >>> type(g[1]) is WVertex
        True
        >>> g[2] = {1: 4, 3: 9} #non-existent vertex values get created automatically
        >>> print g             #XXX what if VertexType==Vertex -> how to specify no edge value???
        {1: {}, 2: {1: 4, 3: 9}, 3: {}}
        >>> g._validate()
        >>>
        """
        if isinstance(value, self.VertexType) and value._id == vid and value._graph == self:
            dict.__setitem__(self, vid, value)
        else:        #convert to VertexType or create copy of VertexType
            dict.__setitem__(self, vid, self.VertexType(self, vid, value)) #XXX shallow copy

    def __delitem__(self, head):
        """Delete a single vertex and associated edges.