Method add_node

networkx/classes/graph.py:535–582

Add a single node `node_for_adding` and update node attributes. Parameters ---------- node_for_adding : node A node can be any hashable Python object except None. attr : keyword arguments, optional Set or change node attributes using key=value

(self, node_for_adding, **attr)

        return self.adj[n]

    def add_node(self, node_for_adding, **attr):
        """Add a single node `node_for_adding` and update node attributes.

        Parameters
        ----------
        node_for_adding : node
            A node can be any hashable Python object except None.
        attr : keyword arguments, optional
            Set or change node attributes using key=value.

        See Also
        --------
        add_nodes_from

        Examples
        --------
        >>> G = nx.Graph()  # or DiGraph, MultiGraph, MultiDiGraph, etc
        >>> G.add_node(1)
        >>> G.add_node("Hello")
        >>> K3 = nx.Graph([(0, 1), (1, 2), (2, 0)])
        >>> G.add_node(K3)
        >>> G.number_of_nodes()
        3

        Use keywords set/change node attributes:

        >>> G.add_node(1, size=10)
        >>> G.add_node(3, weight=0.4, UTM=("13S", 382871, 3972649))

        Notes
        -----
        A hashable object is one that can be used as a key in a Python
        dictionary. This includes strings, numbers, tuples of strings
        and numbers, etc.

        On many platforms hashable items also include mutables such as
        NetworkX Graphs, though one should be careful that the hash
        doesn't change on mutables.
        """
        if node_for_adding not in self._node:
            if node_for_adding is None:
                raise ValueError("None cannot be a node")
            self._adj[node_for_adding] = self.adjlist_inner_dict_factory()
            attr_dict = self._node[node_for_adding] = self.node_attr_dict_factory()
            attr_dict.update(attr)
        else:  # update attr even if node already exists
            self._node[node_for_adding].update(attr)
        nx._clear_cache(self)

    def add_nodes_from(self, nodes_for_adding, **attr):
        """Add multiple nodes.