Create network from dataframe using common column

Question

I'm currently trying to generate a Network-Graph with NetworkX on Python. The Dataset has the following format (it's a CSV):

Id, Tag
0, 'science'
0, 'history'
1, 'sports'
3, 'sci-fi'
3, 'history'
3, 'music'

The Goal is to show the relation between the tags. F.e. Science is really closely related to History because they share the same Id. Now here's where I'm stuck: How can I create a Table/Matrix that has 2 columns for NetworkX to use as Source(-Tag) and Target(-Tag) with Python?

I tried creating a Dataframe with Pandas and then using the same column twice, but that didn't work for me.

What did you try so far? Please provide a minimal an verifiable example — cvanelteren
– cvanelteren, Commented Apr 2, 2020 at 14:04

yatu · Accepted Answer · 2020-04-02 14:17:13Z

1

To connect nodes based on the Id, here's one approach, you can gruopby the Id, aggregate the groups to lists, and build a directed graph adding the lists as paths:

df = pd.read_csv('my_file.csv', sep=', ')
l = df.groupby('Id').Tag.agg(list).tolist()
# [['science', 'history'], ['sports'], ['sci-fi', 'history', 'music']]

G=nx.Graph()
for sl in l:
    nx.add_path(G, sl)

nx.draw(G, node_color='lightblue', 
        with_labels=True, 
        node_size=800)

For a directed graph:

G=nx.DiGraph()
for sl in l:
    nx.add_path(G, sl)

nx.draw(G, node_color='lightblue', 
        with_labels=True, 
        node_size=800)

edited Apr 2, 2020 at 14:17

answered Apr 2, 2020 at 14:05

yatu

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2 Comments

HelloNirvanaNorway Over a year ago

Thanks a lot, that's exactly what i was looking for! :) Do you know if there's any way to optimize l = df.groupby('Id').Tag.agg(list).tolist() ? It get's really slow with bigger sets...

yatu Over a year ago

No prob :) Try df.groupby('Id').Tag.agg(list).values.tolist() @HelloNirvanaNorway

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