MultiDiGraph.add_edges_from#

MultiDiGraph.add_edges_from(ebunch_to_add, **attr)#

Add all the edges in ebunch_to_add.

Parameters:
ebunch_to_addcontainer of edges

Each edge given in the container will be added to the graph. The edges can be:

  • 2-tuples (u, v) or

  • 3-tuples (u, v, d) for an edge data dict d, or

  • 3-tuples (u, v, k) for not iterable key k, or

  • 4-tuples (u, v, k, d) for an edge with data and key k

attrkeyword arguments, optional

Edge data (or labels or objects) can be assigned using keyword arguments.

Returns:
A list of edge keys assigned to the edges in ebunch.

See also

add_edge

add a single edge

add_weighted_edges_from

convenient way to add weighted edges

Notes

Adding the same edge twice has no effect but any edge data will be updated when each duplicate edge is added.

Edge attributes specified in an ebunch take precedence over attributes specified via keyword arguments.

Default keys are generated using the method new_edge_key(). This method can be overridden by subclassing the base class and providing a custom new_edge_key() method.

When adding edges from an iterator over the graph you are changing, a RuntimeError can be raised with message: RuntimeError: dictionary changed size during iteration. This happens when the graph’s underlying dictionary is modified during iteration. To avoid this error, evaluate the iterator into a separate object, e.g. by using list(iterator_of_edges), and pass this object to G.add_edges_from.

Examples

>>> G = nx.Graph()  # or DiGraph, MultiGraph, MultiDiGraph, etc
>>> G.add_edges_from([(0, 1), (1, 2)])  # using a list of edge tuples
>>> e = zip(range(0, 3), range(1, 4))
>>> G.add_edges_from(e)  # Add the path graph 0-1-2-3

Associate data to edges

>>> G.add_edges_from([(1, 2), (2, 3)], weight=3)
>>> G.add_edges_from([(3, 4), (1, 4)], label="WN2898")

Evaluate an iterator over a graph if using it to modify the same graph

>>> G = nx.MultiGraph([(1, 2), (2, 3), (3, 4)])
>>> # Grow graph by one new node, adding edges to all existing nodes.
>>> # wrong way - will raise RuntimeError
>>> # G.add_edges_from(((5, n) for n in G.nodes))
>>> # right way - note that there will be no self-edge for node 5
>>> assigned_keys = G.add_edges_from(list((5, n) for n in G.nodes))
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