calculate neighbors with NetworkX (error: The node 0 is not in the graph.)

Question

I have a sample dataframe with a column for ‘to’, a column for ‘from’ and several columns for features relating to either the ‘to’ or ‘from’ colum.

I used G = nx.from_pandas_edgelist(df, source='to', target='from',edge_attr=True) to convert the dataframe to a NetworkX graph. I used edge_attr=True because I would like to keep the features for future analysis.

I want to calculate the number of neighbours for each point, so I used neighbours = nx.all_neighbors(G,0) however, I get the error ‘The node 0 is not in the graph.’

I’m not sure what I’m doing wrong.

import pandas as pd
import networkx as nx

df = pd.DataFrame({'to':[78,18,94,55,68,57,78,8],
                   'from':[18,78,35,14,57,68,57,17],
                   'to_Attribute_1':[18,78,35,14,57,68,57,17],
                   'to_Attribute_2':[18,78,35,14,57,68,57,17],
                   'from_Attribute_1':[18,78,35,14,57,68,57,17],
                   'from_Attribute_2':[18,78,35,14,57,68,57,17],
                  })
G = nx.from_pandas_edgelist(df, source='to', target='from',edge_attr=True)
[e for e in G.edges]

neighbours = nx.all_neighbors(G,0)

Asked By: Rebecca James

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Source

Answer 1

You should loop over the graph’s nodes:


neighbours = {n: len(list(nx.all_neighbors(G, n))) for n in G.nodes}

Output (node -> number of neighbors):

{78: 2, 18: 1, 94: 1, 35: 1, 55: 1, 14: 1, 68: 1, 57: 2, 8: 1, 17: 1}

Answered By: mozway

calculate neighbors with NetworkX (error: The node 0 is not in the graph.)

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