Edgelist

These methods provide the importers’ functionality without actually constructing a graph. They simply return an in-memory edge list. This is helpful for example in order to bulk load a sparse graph, or to perform some preprocessing before loading a graph.

jgrapht.io.edgelist.parse_edgelist_csv(input_string, format='adjacencylist', import_edge_weights=False, matrix_format_node_id=False, matrix_format_zero_when_noedge=True)[source]

Imports a graph as an edgelist from a string in CSV Format.

The importer supports various different formats which can be adjusted using the format parameter. The supported formats are the same CSV formats used by Gephi. The importer respects rfc4180.

Parameters

  • input_string – the input string to read from

  • format – format to use. One of “edgelist”, “adjacencylist” and “matrix”

  • import_edge_weights – whether to import edge weights

  • matrix_format_node_id – only for the matrix format, whether to import node identifiers

  • matrix_format_zero_when_noedge – only for the matrix format, whether the input contains zero for missing edges

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – in case of an import error

jgrapht.io.edgelist.parse_edgelist_dimacs(input_string, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Read graph in DIMACS format from string.

For a description of the formats see http://dimacs.rutgers.edu/Challenges . Note that there a lot of different formats based on each different challenge. The importer supports the shortest path challenge format, the coloring format and the maximum-clique challenge formats.

Note

In DIMACS formats the vertices are integers numbered from one. The importer automatically translates them to zero-based numbering.

Briefly, one of the most common DIMACS formats is the 2nd DIMACS challenge and follows the following structure:

DIMACS G {
  c <comments> ignored during parsing of the graph
  p edge <number of nodes> <number of edges>
  e <edge source 1> <edge target 1>
  e <edge source 2> <edge target 2>
  e <edge source 3> <edge target 3>
  e <edge source 4> <edge target 4>
  ...
}

Although not specified directly in the DIMACS format documentation, this implementation also allows for the a weighted variant:

e <edge source 1> <edge target 1> <edge_weight>

Note

This implementation does not fully implement the DIMACS specifications! Special fields specified as ‘Optional Descriptors’ are ignored.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • input_string – Input string to read from

  • vertex_attribute_cb – Callback function for vertex attributes

  • edge_attribute_cb – Callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – In case of an import error

jgrapht.io.edgelist.parse_edgelist_dot(input_string, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Read a graph as an edgelist from a string in DOT format.

For a description of the format see https://en.wikipedia.org/wiki/DOT_language and http://www.graphviz.org/doc/info/lang.html .

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • input_string – the input string to read from

  • vertex_attribute_cb – callback function for vertex attributes

  • edge_attribute_cb – callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – in case of an import error

jgrapht.io.edgelist.parse_edgelist_gexf(input_string, import_id_cb=None, validate_schema=True, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Imports a graph as an edgelist from a GEXF input string.

This is a simple implementation with supports only a limited set of features of the GEXF specification, oriented towards parsing speed. Moreover, it notifies lazily and completely out-of-order for any additional vertex and edge attributes in the input file. Users can register callbacks for vertex and edge attributes. Finally, default attribute values and any nested elements are completely ignored.

For a description of the format see https://gephi.org/gexf/format/index.html or the GEXF Primer.

Below is small example of a graph in GEXF format:

<?xml version="1.0" encoding="UTF-8"?>
<gexf xmlns="http://www.gexf.net/1.2draft"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.gexf.net/1.2draft http://www.gexf.net/1.2draft/gexf.xsd"
    version="1.2">
    <graph defaultedgetype="undirected">
        <nodes>
        <node id="n0" label="node 0"/>
        <node id="n1" label="node 1"/>
        <node id="n2" label="node 2"/>
        <node id="n3" label="node 3"/>
        <node id="n4" label="node 4"/>
        <node id="n5" label="node 5"/>
        </nodes>
        <edges>
        <edge id="e0" source="n0" target="n2" weight="1.0"/>
        <edge id="e1" source="n0" target="n1" weight="1.0"/>
        <edge id="e2" source="n1" target="n3" weight="2.0"/>
        <edge id="e3" source="n3" target="n2"/>
        <edge id="e4" source="n2" target="n4"/>
        <edge id="e5" source="n3" target="n5"/>
        <edge id="e6" source="n5" target="n4" weight="1.1"/>
        </edges>
    </graph>
</gexf>

The parser completely ignores the global attribute “defaultedgetype” and the edge attribute “type” which denotes whether an edge is directed or not. The importer by default validates the input using the 1.2draft GEXF Schema. The user can (not recommended) disable the validation by adjusting the appropriate parameter. Older schemas are not supported.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • input_string – the input string to read from

  • validate_schema – whether to validate the XML schema

  • vertex_attribute_cb – callback function for vertex attributes

  • edge_attribute_cb – callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – in case of an import error

jgrapht.io.edgelist.parse_edgelist_gml(input_string, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Read a graph as an edgelist from a string in GML format (Graph Modelling Language).

For a description of the format see http://www.infosun.fmi.uni-passau.de/Graphlet/GML/. Below is small example of a graph in GML format.:

graph [
    node [
        id 1
    ]
    node [
        id 2
        label "Node 2 has an optional label"
    ]
    node [
        id 3
    ]
    edge [
        source 1
        target 2
        weight 2.0
        label "Edge between 1 and 2"
    ]
    edge [
        source 2
        target 3
        weight 3.0
        label "Edge between 2 and 3"
    ]
]

The importer also supports reading additional string attributes such as label or custom user attributes. String attributes are unescaped as if they are Java strings.

The parser completely ignores elements from the input that are not related to vertices or edges of the graph. Moreover, complicated nested structures are simply returned as a whole. For example, in the following graph:

graph [
    node [
        id 1
    ]
    node [
        id 2
    ]
    edge [
        source 1
        target 2
        points [ x 1.0 y 2.0 ]
    ]
]

the points attribute of the edge is returned as a string containing “[ x 1.0 y 2.0 ]”.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • graph – The graph to read into

  • input_string – Input string to read from

  • vertex_attribute_cb – Callback function for vertex attributes

  • edge_attribute_cb – Callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – In case of an import error

jgrapht.io.edgelist.parse_edgelist_graph6sparse6(input_string, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Read a graph as an edgelist from a string in graph6 or sparse6 format.

See https://users.cecs.anu.edu.au/~bdm/data/formats.txt for a description of the format. Both graph6 and sparse6 are formats for storing undirected graphs, using a small number of printable ASCII characters. Graph6 is suitable for small graphs or large dense graphs while sparse6 is better for large sparse graphs. Moreover, sparse6 supports self-loops and multiple-edges while graph6 does not.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • input_string – the input string

  • vertex_attribute_cb – callback function for vertex attributes

  • edge_attribute_cb – callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – in case of an import error

jgrapht.io.edgelist.parse_edgelist_graphml(input_string, validate_schema=True, vertex_attribute_cb=None, edge_attribute_cb=None, simple=True)[source]

Imports a graph as an edgelist from a GraphML input string.

For a description of the format see http://en.wikipedia.org/wiki/GraphML or the GraphML Primer.

Below is a small example in GraphML:

<?xml version="1.0" encoding="UTF-8"?>
<graphml xmlns="http://graphml.graphdrawing.org/xmlns"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns
    http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
    <key id="d0" for="node" attr.name="color" attr.type="string" />
    <key id="d1" for="edge" attr.name="weight" attr.type="double"/>
    <graph id="G" edgedefault="undirected">
        <node id="n0">
            <data key="d0">green</data>
        </node>
        <node id="n1">
            <data key="d0">black</data>
        </node>
        <node id="n2">
            <data key="d0">blue</data>
        </node>
        <node id="n3">
            <data key="d0">red</data>
        </node>
        <node id="n4">
            <data key="d0">white</data>
        </node>
        <node id="n5">
            <data key="d0">turquoise</data>
        </node>
        <edge id="e0" source="n0" target="n2">
            <data key="d1">1.0</data>
        </edge>
        <edge id="e1" source="n0" target="n1">
            <data key="d1">1.0</data>
        </edge>
        <edge id="e2" source="n1" target="n3">
            <data key="d1">2.0</data>
        </edge>
        <edge id="e3" source="n3" target="n2"/>
        <edge id="e4" source="n2" target="n4"/>
        <edge id="e5" source="n3" target="n5"/>
        <edge id="e6" source="n5" target="n4">
            <data key="d1">1.1</data>
        </edge>
    </graph>
</graphml>

In case the graph is weighted and the corresponding edge attribute “weight” is defined, the importer also reads edge weights. Otherwise edge weights are ignored. Moreover, the parser completely ignores the global attribute “edgedefault” which denotes whether an edge is directed or not. Whether edges are directed or not depends on the underlying implementation of the user provided graph object.

The importer by default validates the input using 1.0 GraphML Schema. The user can (not recommended) disable the validation by adjusting the appropriate parameter.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Note

The parameter simple affect the capabilities of the importer. It trades functionality for parsing speed.

Parameters

  • input_string – the input string to read from

  • validate_schema – whether to validate the XML schema

  • vertex_attribute_cb – callback function for vertex attributes

  • edge_attribute_cb – callback function for edge attributes

  • simple – whether to use a simpler parser with more speed but less functionality

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – in case of an import error

jgrapht.io.edgelist.parse_edgelist_json(input_string, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Import a graph as an edgelist from a JSON string.

Below is a small example of a graph in JSON format:

{
    "nodes": [
        { "id": "1" },
        { "id": "2", "label": "Node 2 label" },
        { "id": "3" }
    ],
    "edges": [
        { "source": "1", "target": "2", "weight": 2.0, "label": "Edge between 1 and 2" },
        { "source": "2", "target": "3", "weight": 3.0, "label": "Edge between 2 and 3" }
    ]
}

The importer also supports reading additional string attributes such as label or custom user attributes. The parser completely ignores elements from the input that are not related to vertices or edges of the graph. Moreover, complicated nested structures which are inside vertices or edges are simply returned as a whole. For example, in the following graph:

{
    "nodes": [
        { "id": "1" },
        { "id": "2" }
    ],
    "edges": [
        { "source": "1", "target": "2", "points": { "x": 1.0, "y": 2.0 } }
    ]
}

the points attribute of the edge is returned as a string containing {“x”:1.0,”y”:2.0}. The same is done for arrays or any other arbitrary nested structure.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • input_string – The input string to read from

  • vertex_attribute_cb – Callback function for vertex attributes

  • edge_attribute_cb – Callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – In case of an import error

jgrapht.io.edgelist.read_edgelist_csv(filename, format='adjacencylist', import_edge_weights=False, matrix_format_node_id=False, matrix_format_zero_when_noedge=True)[source]

Imports a graph as an edgelist from a file in CSV Format.

The importer supports various different formats which can be adjusted using the format parameter. The supported formats are the same CSV formats used by Gephi. The importer respects rfc4180.

Parameters

  • filename – the filename to read from

  • format – format to use. One of “edgelist”, “adjacencylist” and “matrix”

  • import_edge_weights – whether to import edge weights

  • matrix_format_node_id – only for the matrix format, whether to import node identifiers

  • matrix_format_zero_when_noedge – only for the matrix format, whether the input contains zero for missing edges

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – in case of an import error

jgrapht.io.edgelist.read_edgelist_dimacs(filename, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Read a graph as an edgelist from a file in DIMACS format.

For a description of the formats see http://dimacs.rutgers.edu/Challenges . Note that there a lot of different formats based on each different challenge. The importer supports the shortest path challenge format, the coloring format and the maximum-clique challenge formats.

Note

In DIMACS formats the vertices are integers numbered from one. The importer automatically translates them to zero-based numbering.

Briefly, one of the most common DIMACS formats is the 2nd DIMACS challenge and follows the following structure:

DIMACS G {
  c <comments> ignored during parsing of the graph
  p edge <number of nodes> <number of edges>
  e <edge source 1> <edge target 1>
  e <edge source 2> <edge target 2>
  e <edge source 3> <edge target 3>
  e <edge source 4> <edge target 4>
  ...
}

Although not specified directly in the DIMACS format documentation, this implementation also allows for the a weighted variant:

e <edge source 1> <edge target 1> <edge_weight>

Note

This implementation does not fully implement the DIMACS specifications! Special fields specified as ‘Optional Descriptors’ are ignored.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • filename – filename to read from

  • vertex_attribute_cb – Callback function for vertex attributes

  • edge_attribute_cb – Callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – In case of an import error

jgrapht.io.edgelist.read_edgelist_dot(filename, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Read a graph as an edgelist from a file in DOT format.

For a description of the format see https://en.wikipedia.org/wiki/DOT_language and http://www.graphviz.org/doc/info/lang.html .

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • filename – Filename to read from

  • vertex_attribute_cb – Callback function for vertex attributes

  • edge_attribute_cb – Callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – In case of an import error

jgrapht.io.edgelist.read_edgelist_gexf(filename, validate_schema=True, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Imports a graph as an edgelist from a GEXF file.

This is a simple implementation with supports only a limited set of features of the GEXF specification, oriented towards parsing speed. Moreover, it notifies lazily and completely out-of-order for any additional vertex and edge attributes in the input file. Users can register callbacks for vertex and edge attributes. Finally, default attribute values and any nested elements are completely ignored.

For a description of the format see https://gephi.org/gexf/format/index.html or the GEXF Primer.

Below is small example of a graph in GEXF format:

<?xml version="1.0" encoding="UTF-8"?>
<gexf xmlns="http://www.gexf.net/1.2draft"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.gexf.net/1.2draft http://www.gexf.net/1.2draft/gexf.xsd"
    version="1.2">
    <graph defaultedgetype="undirected">
        <nodes>
        <node id="n0" label="node 0"/>
        <node id="n1" label="node 1"/>
        <node id="n2" label="node 2"/>
        <node id="n3" label="node 3"/>
        <node id="n4" label="node 4"/>
        <node id="n5" label="node 5"/>
        </nodes>
        <edges>
        <edge id="e0" source="n0" target="n2" weight="1.0"/>
        <edge id="e1" source="n0" target="n1" weight="1.0"/>
        <edge id="e2" source="n1" target="n3" weight="2.0"/>
        <edge id="e3" source="n3" target="n2"/>
        <edge id="e4" source="n2" target="n4"/>
        <edge id="e5" source="n3" target="n5"/>
        <edge id="e6" source="n5" target="n4" weight="1.1"/>
        </edges>
    </graph>
</gexf>

The parser completely ignores the global attribute “defaultedgetype” and the edge attribute “type” which denotes whether an edge is directed or not. The importer by default validates the input using the 1.2draft GEXF Schema. The user can (not recommended) disable the validation by adjusting the appropriate parameter. Older schemas are not supported.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • filename – the input file to read from

  • validate_schema – whether to validate the XML schema

  • vertex_attribute_cb – callback function for vertex attributes

  • edge_attribute_cb – callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – in case of an import error

jgrapht.io.edgelist.read_edgelist_gml(filename, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Read a graph as an edgelist from a file in GML format (Graph Modelling Language).

For a description of the format see http://www.infosun.fmi.uni-passau.de/Graphlet/GML/. Below is small example of a graph in GML format.:

graph [
    node [
        id 1
    ]
    node [
        id 2
        label "Node 2 has an optional label"
    ]
    node [
        id 3
    ]
    edge [
        source 1
        target 2
        weight 2.0
        label "Edge between 1 and 2"
    ]
    edge [
        source 2
        target 3
        weight 3.0
        label "Edge between 2 and 3"
    ]
]

The importer also supports reading additional string attributes such as label or custom user attributes. String attributes are unescaped as if they are Java strings.

The parser completely ignores elements from the input that are not related to vertices or edges of the graph. Moreover, complicated nested structures are simply returned as a whole. For example, in the following graph:

graph [
    node [
        id 1
    ]
    node [
        id 2
    ]
    edge [
        source 1
        target 2
        points [ x 1.0 y 2.0 ]
    ]
]

the points attribute of the edge is returned as a string containing “[ x 1.0 y 2.0 ]”.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • filename – Filename to read from

  • vertex_attribute_cb – Callback function for vertex attributes

  • edge_attribute_cb – Callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – In case of an import error

jgrapht.io.edgelist.read_edgelist_graph6sparse6(filename, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Read a graph as an edgelist from a file in graph6 or sparse6 format.

See https://users.cecs.anu.edu.au/~bdm/data/formats.txt for a description of the format. Both graph6 and sparse6 are formats for storing undirected graphs, using a small number of printable ASCII characters. Graph6 is suitable for small graphs or large dense graphs while sparse6 is better for large sparse graphs. Moreover, sparse6 supports self-loops and multiple-edges while graph6 does not.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • filename – filename to read from

  • vertex_attribute_cb – callback function for vertex attributes

  • edge_attribute_cb – callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – in case of an import error

jgrapht.io.edgelist.read_edgelist_graphml(filename, validate_schema=True, vertex_attribute_cb=None, edge_attribute_cb=None, simple=True)[source]

Imports a graph as an edge list from a GraphML file.

For a description of the format see http://en.wikipedia.org/wiki/GraphML or the GraphML Primer.

Below is a small example in GraphML:

<?xml version="1.0" encoding="UTF-8"?>
<graphml xmlns="http://graphml.graphdrawing.org/xmlns"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns
    http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
    <key id="d0" for="node" attr.name="color" attr.type="string" />
    <key id="d1" for="edge" attr.name="weight" attr.type="double"/>
    <graph id="G" edgedefault="undirected">
        <node id="n0">
            <data key="d0">green</data>
        </node>
        <node id="n1">
            <data key="d0">black</data>
        </node>
        <node id="n2">
            <data key="d0">blue</data>
        </node>
        <node id="n3">
            <data key="d0">red</data>
        </node>
        <node id="n4">
            <data key="d0">white</data>
        </node>
        <node id="n5">
            <data key="d0">turquoise</data>
        </node>
        <edge id="e0" source="n0" target="n2">
            <data key="d1">1.0</data>
        </edge>
        <edge id="e1" source="n0" target="n1">
            <data key="d1">1.0</data>
        </edge>
        <edge id="e2" source="n1" target="n3">
            <data key="d1">2.0</data>
        </edge>
        <edge id="e3" source="n3" target="n2"/>
        <edge id="e4" source="n2" target="n4"/>
        <edge id="e5" source="n3" target="n5"/>
        <edge id="e6" source="n5" target="n4">
            <data key="d1">1.1</data>
        </edge>
    </graph>
</graphml>

The importer reads the input into a graph which is provided by the user. In case the graph is weighted and the corresponding edge attribute “weight” is defined, the importer also reads edge weights. Otherwise edge weights are ignored. Moreover, the parser completely ignores the global attribute “edgedefault” which denotes whether an edge is directed or not.

The importer by default validates the input using 1.0 GraphML Schema. The user can (not recommended) disable the validation by adjusting the appropriate parameter.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Note

The parameter simple affect the capabilities of the importer. It trades functionality for parsing speed.

Parameters

  • filename – the input file to read from

  • validate_schema – whether to validate the XML schema

  • vertex_attribute_cb – callback function for vertex attributes

  • edge_attribute_cb – callback function for edge attributes

  • simple – whether to use a simpler parser with more speed but less functionality

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – in case of an import error

jgrapht.io.edgelist.read_edgelist_json(filename, vertex_attribute_cb=None, edge_attribute_cb=None)[source]

Read a graph as an edgelist from a JSON file.

Below is a small example of a graph in JSON format:

{
    "nodes": [
        { "id": "1" },
        { "id": "2", "label": "Node 2 label" },
        { "id": "3" }
    ],
    "edges": [
        { "source": "1", "target": "2", "weight": 2.0, "label": "Edge between 1 and 2" },
        { "source": "2", "target": "3", "weight": 3.0, "label": "Edge between 2 and 3" }
    ]
}

The importer also supports reading additional string attributes such as label or custom user attributes. The parser completely ignores elements from the input that are not related to vertices or edges of the graph. Moreover, complicated nested structures which are inside vertices or edges are simply returned as a whole. For example, in the following graph:

{
    "nodes": [
        { "id": "1" },
        { "id": "2" }
    ],
    "edges": [
        { "source": "1", "target": "2", "points": { "x": 1.0, "y": 2.0 } }
    ]
}

the points attribute of the edge is returned as a string containing {“x”:1.0,”y”:2.0}. The same is done for arrays or any other arbitrary nested structure.

Note

Attribute callback functions accept three parameters. The first is the vertex or edge identifier. The second is the attribute key and the third is the attribute value. For the vertices the identifier is a string read from the input. For the edges the identifier is an integer denoting the rank of the particular edge in the returned edge list.

Parameters

  • filename – Filename to read from

  • vertex_attribute_cb – Callback function for vertex attributes

  • edge_attribute_cb – Callback function for edge attributes

Returns

an edge list. This is an iterable which returns iterators of named tuples(source, target, weight)

Raises

IOError – In case of an import error