CODEWITHSUNDEEP
pythontuplesnetworkx
Giulio Mario Martena
Giulio Mario Martena

Reputation: 39

How to build graph paths from list of nodes in NetworkX

What I am trying to do is build a graph in NetworkX, in which every node is a train station. To build the nodes I did:

G = nx.Graph()
G.add_nodes_from(trains['Stopping place'].unique())

which (at least as it looks like) it's working.
Now, since for each line I have the stops in sequence, I built my paths like so:

stops_by_line = ((belgium_trains.sort_values(['Train number','Actual arrival datetime']).groupby('Train number'))['Stopping place'].apply(list).to_dict())
paths = ([tuple(val) for val in stops_by_line.values()])

and the variable looks like this:

[('HERGENRATH',
'CHENEE',
'ANGLEUR',
'LIEGE-GUILLEMINS',
'ANS',
'LEUVEN',
'HERENT',
'VELTEM',
'ERPS-KWERPS',
'KORTENBERG',
'NOSSEGEM',
'ZAVENTEM',
'DIEGEM',
'HAREN-ZUID',
'SCHAARBEEK',
'BRUSSEL-NOORD',
'BRUSSEL-CONGRES',
'BRUSSEL-CENTRAAL',
'BRUSSEL-KAPELLEKERK',
'BRUSSEL-ZUID'),
(...other ordered tuples of stops),...)]

Now my question is, since all of these elements are also node names, how can I build the edges using these tuples sequentially (for example add an edge between BRUSSEL-NOORD and BRUSSEL-CONGRES, then from BRUSSEL-CONGRES to BRUSSEL-CENTRAAL and so on)?

Upvotes: 1

Views: 1241

Answers (1)

Sparky05
Sparky05

Reputation: 4892

You can simply use the add_path method in a loop:

for path in paths:
    nx.add_path(G, path)

Sidemark, if you add an edge (like e.g. above), then networkx also directly adds the respective nodes to the graph. So probably (if all stops are covered by some train) you don't need to add the nodes manually before.

Upvotes: 1

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