networkx.relabel.relabel_nodes

relabel_nodes(G, mapping, copy=True)[source]

Relabel the nodes of the graph G.

Parameters
  • G (graph) – A NetworkX graph

  • mapping (dictionary) – A dictionary with the old labels as keys and new labels as values. A partial mapping is allowed.

  • copy (bool (optional, default=True)) – If True return a copy, or if False relabel the nodes in place.

Examples

To create a new graph with nodes relabeled according to a given dictionary:

>>> G = nx.path_graph(3)
>>> sorted(G)
[0, 1, 2]
>>> mapping = {0: 'a', 1: 'b', 2: 'c'}
>>> H = nx.relabel_nodes(G, mapping)
>>> sorted(H)
['a', 'b', 'c']

Nodes can be relabeled with any hashable object, including numbers and strings:

>>> import string
>>> G = nx.path_graph(26)  # nodes are integers 0 through 25
>>> sorted(G)[:3]
[0, 1, 2]
>>> mapping = dict(zip(G, string.ascii_lowercase))
>>> G = nx.relabel_nodes(G, mapping) # nodes are characters a through z
>>> sorted(G)[:3]
['a', 'b', 'c']
>>> mapping = dict(zip(G, range(1, 27)))
>>> G = nx.relabel_nodes(G, mapping)  # nodes are integers 1 through 26
>>> sorted(G)[:3]
[1, 2, 3]

To perform a partial in-place relabeling, provide a dictionary mapping only a subset of the nodes, and set the copy keyword argument to False:

>>> G = nx.path_graph(3)  # nodes 0-1-2
>>> mapping = {0: 'a', 1: 'b'} # 0->'a' and 1->'b'
>>> G = nx.relabel_nodes(G, mapping, copy=False)
>>> sorted(G, key=str)
[2, 'a', 'b']

A mapping can also be given as a function:

>>> G = nx.path_graph(3)
>>> H = nx.relabel_nodes(G, lambda x: x ** 2)
>>> list(H)
[0, 1, 4]

Notes

Only the nodes specified in the mapping will be relabeled.

The keyword setting copy=False modifies the graph in place. Relabel_nodes avoids naming collisions by building a directed graph from mapping which specifies the order of relabelings. Naming collisions, such as a->b, b->c, are ordered such that “b” gets renamed to “c” before “a” gets renamed “b”. In cases of circular mappings (e.g. a->b, b->a), modifying the graph is not possible in-place and an exception is raised. In that case, use copy=True.