This documents an unmaintained version of NetworkX. Please upgrade to a maintained version and see the current NetworkX documentation.


write_edgelist(G, path, comments='#', delimiter=' ', data=True, encoding='utf-8')[source]

Write graph as a list of edges.

  • G (graph) – A NetworkX graph
  • path (file or string) – File or filename to write. If a file is provided, it must be opened in ‘wb’ mode. Filenames ending in .gz or .bz2 will be compressed.
  • comments (string, optional) – The character used to indicate the start of a comment
  • delimiter (string, optional) – The string used to separate values. The default is whitespace.
  • data (bool or list, optional) – If False write no edge data. If True write a string representation of the edge data dictionary.. If a list (or other iterable) is provided, write the keys specified in the list.
  • encoding (string, optional) – Specify which encoding to use when writing file.


>>> G=nx.path_graph(4)
>>> nx.write_edgelist(G, "test.edgelist")
>>> G=nx.path_graph(4)
>>> fh=open("test.edgelist",'wb')
>>> nx.write_edgelist(G, fh)
>>> nx.write_edgelist(G, "test.edgelist.gz")
>>> nx.write_edgelist(G, "test.edgelist.gz", data=False)
>>> G=nx.Graph()
>>> G.add_edge(1,2,weight=7,color='red')
>>> nx.write_edgelist(G,'test.edgelist',data=False)
>>> nx.write_edgelist(G,'test.edgelist',data=['color'])
>>> nx.write_edgelist(G,'test.edgelist',data=['color','weight'])