neighbors=G.neighbors_iter AttributeError: 'Graph' object has no attribute 'neighbors_iter'

Question

import networkx as nx 
def core_number(G):
    nodes=list(G.nodes())
    if G.is_multigraph():
        raise nx.NetworkXError('MultiGraph and MultiDiGraph types not supported.')

    if G.number_of_selfloops()>0:
        raise nx.NetworkXError('Input graph has self loops; the core number is not defined.','Consider using G.remove_edges_from(G.selfloop_edges()).')

    if G.is_directed():
        def neighbors(v):
            return itertools.chain.from_iterable([G.predecessors_iter(v), G.successors_iter(v)])
    else:
        neighbors=G.neighbors_iter
    return neighbors

I am working with python3 and networkx-2.0. The above code give the following error:

   neighbors=G.neighbors_iter()
   AttributeError: 'Graph' object has no attribute 'neighbors_iter'

Answer 1

NetworkX 2.0 makes breaking API changes. Code written for 1.x will need migration . For example, quoting the migration guide,

Methods that used to return containers now return iterators and methods that returned iterators have been removed.

neighbors_iter isn't a thing any more; neighbors does that job now. Similarly, predecessors_iter and successors_iter don't exist either.

(Also, NetworkX 2.0 isn't even out yet. You probably shouldn't be using the development branch.)