Pajek (.net)
Background & Context
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- Pajek graph language and data format.
- Commonly used exchange format for graphs.
- Native format of the Pajek network analysis software.
- The format name is Slovenian for spider.
- Stores a single directed, undirected, or mixed graph.
- Can contain user-defined edge and vertex attributes.
- Plain text format.
- Developed in 1996 by researchers at Ljubljana University.
Import & Export
- Import["file.net"] gives a Graph object representing the graph stored in the specified file.
- Export["file.net",expr] exports an adjacency matrix or edge information representing a graph to the Pajek format.
- Import["file.net"] imports the graph from file and returns it as a Graph.
- Import["file.net",elem] imports the specified element from a Pajek file.
- Import["file.net",{{elem1,elem2,…}}] imports multiple elements.
- The import format can be specified with Import["file","Pajek"] or Import["file",{"Pajek",elem,…}].
- Export["file.net",expr,elem] creates a Pajek file by treating expr as specifying element elem.
- Export["file.net",{expr1,expr2,…},{{elem1,elem2,…}}] treats each expri as specifying the corresponding elemi.
- Export["file.net",expr,opt1->val1,…] exports expr with the specified option elements taken to have the specified values.
- Export["file.net",{elem1->expr1,elem2->expr2,…},"Rules"] uses rules to specify the elements to be exported.
- See the following reference pages for full general information:
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Import, Export import from or export to a file CloudImport, CloudExport import from or export to a cloud object ImportString, ExportString import from or export to a string ImportByteArray, ExportByteArray import from or export to a byte array
Import Elements
- General Import elements:
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"Elements" list of elements and options available in this file "Summary" summary of the file "Rules" list of rules for all available elements - Data representation elements:
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"AdjacencyMatrix" edge information, given as a matrix "EdgeAttributes" edge attributes, represented as a list of rules "EdgeRules" connectivity data for the graph, given as a list of rules "EdgeRulesDirected" directed edges "EdgeRulesUndirected" undirected edges "Graph" graph stored in the file, given as a Graph object "Graphics" graph stored in the file, rendered as a graph plot "VertexAttributes" vertex attributes, represented as a list of rules "VertexCount" number of vertices in the graph - Import by default uses the "Graph" element when importing from Pajek.
Options
- General Import options:
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ImageSize Automatic specifies the overall size of the image to display for a graph - When importing from Pajek, all options supported by Graph can be given. Common settings include:
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EdgeLabels Automatic labels and label placement for edge EdgeWeight Automatic weight for edge VertexCoordinates Automatic center coordinate for vertex VertexLabels Automatic labels and label placement for vertex VertexShape Automatic graphic shape for vertex - When importing "Graphics", all options supported by GraphPlot can be given. Common settings include:
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DirectedEdges Automatic whether to show edges as directed arrows EdgeLabels Automatic whether to include labels given for edges EdgeShapeFunction Automatic function to give explicit graphics for edges VertexLabels Automatic whether to show vertex names as labels VertexShapeFunction Automatic function to give explicit graphics for vertices - Export options:
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DirectedEdges Automatic whether the data to be exported represents a directed graph VertexCoordinates Automatic rules for explicit vertex coordinates - When exporting from edge rules or from a symmetric adjacency matrix, edges are taken to be undirected by default.
Examples
Basic Examples (6)
Import a Graph object from a Pajek file:
Show the Import elements available from an example file:
Import the connectivity rules of a graph:
Export a Graph to the Pajek format:
Export an asymmetric adjacency matrix of a graph to the Pajek format:
Convert a list of edge rules representing an undirected graph to the Pajek language: