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How to create a CSV network in Mathematica?

Phil R
Posted 10 years ago

Hi everybody. I have created a CSV file representing a network and now I want to import it in Mathematica and represent it. I import my file, but I can't create the graph . The function Graph doesn't work and GraphPlot gives me an error (is not a valid graph). With the same file I'm able to create the network in Gephi. Could you give me please an example of a CSV file and a network created with it in Mathematica? Thank you in advance.

Regards
POSTED BY: Phil R
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David Keith
David Keith
Posted 10 years ago

** Note: there was an error in the first post and attached notebook which have been corrected . **

The code will depend on how you've chosen to represent the graph in the csv file. The attached assumes the file is a list of pairs representing edges.

SetDirectory[NotebookDirectory[]];

importedEdges = Import["edges.csv"]

undirectedEdges = MapThread[UndirectedEdge, importedEdges // Transpose]

Graph[undirectedEdges, VertexLabels -> "Name"]

enter image description here

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POSTED BY: David Keith
David Keith
David Keith
Posted 10 years ago

Mathematica is extremely versatile. If you can understand the format of the csv file, then you can reformat it as needed. Attached is a new notebook. I did not load csv file -- that's easy with Import. But for the array of 7 rows and 5 columns, I assume the format means that for each row, there is a directed edge from the first element to each of the remaining four. The data is therefor transformed by a rule which maps that structure to a list of 4 edge expressions, when applied to a row. When that rule is applied to the data, we get 7 lists of edges. They are flattened because Graph wants a single level list. If you could attach a perhaps abbreviated csv file and some words about its format I could be of more help.

Kind regards,

David

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POSTED BY: David Keith
Phil R
Phil R
Posted 10 years ago

Thank you David. My network is a bit more complex... So if I have more nodes with more connections between them, I have to write each connection in the csv file as a list of pairs, right? But is there a faster solution? For example I have a complex csv with more rows and columns, with another software like Gephi there are no problems: it recognizes the networks and creates it. In Mathematica this seems to not be possible. Do you have any suggestions? Thank you in advance
POSTED BY: Phil R
Phil R
Phil R
Posted 10 years ago

Thank you David for having solved my problem, that example was really helpful for me. Now Mathematica creates the network graph.

Regards Filippo
POSTED BY: Phil R
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