easygraph.readwrite.edgelist module#

easygraph.readwrite.edgelist.generate_edgelist(G, delimiter=' ', data=True)[source]#

Generate a single line of the graph G in edge list format.

Parameters:

  • G (EasyGraph graph) –

  • delimiter (string, optional) – Separator for node labels

  • data (bool or list of keys) – If False generate no edge data. If True use a dictionary representation of edge data. If a list of keys use a list of data values corresponding to the keys.

Returns:

lines – Lines of data in adjlist format.

Return type:

string

Examples

>>> G = eg.lollipop_graph(4, 3)
>>> G[1][2]["weight"] = 3
>>> G[3][4]["capacity"] = 12
>>> for line in eg.generate_edgelist(G, data=False):
...     print(line)
0 1
0 2
0 3
1 2
1 3
2 3
3 4
4 5
5 6

>>> for line in eg.generate_edgelist(G):
...     print(line)
0 1 {}
0 2 {}
0 3 {}
1 2 {'weight': 3}
1 3 {}
2 3 {}
3 4 {'capacity': 12}
4 5 {}
5 6 {}

>>> for line in eg.generate_edgelist(G, data=["weight"]):
...     print(line)
0 1
0 2
0 3
1 2 3
1 3
2 3
3 4
4 5
5 6

See also

write_adjlist, read_adjlist

easygraph.readwrite.edgelist.parse_edgelist(lines, comments='#', delimiter=None, create_using=None, nodetype=None, data=True)[source]#

Parse lines of an edge list representation of a graph.

Parameters:

  • lines (list or iterator of strings) – Input data in edgelist format

  • comments (string, optional) – Marker for comment lines. Default is ‘#’. To specify that no character should be treated as a comment, use comments=None.

  • delimiter (string, optional) – Separator for node labels. Default is None, meaning any whitespace.

  • create_using (EasyGraph graph constructor, optional (default=eg.Graph)) – Graph type to create. If graph instance, then cleared before populated.

  • nodetype (Python type, optional) – Convert nodes to this type. Default is None, meaning no conversion is performed.

  • data (bool or list of (label,type) tuples) – If False generate no edge data or if True use a dictionary representation of edge data or a list tuples specifying dictionary key names and types for edge data.

Returns:

G – The graph corresponding to lines

Return type:

EasyGraph Graph

Examples

Edgelist with no data:

>>> lines = ["1 2", "2 3", "3 4"]
>>> G = eg.parse_edgelist(lines, nodetype=int)
>>> list(G)
[1, 2, 3, 4]
>>> list(G.edges)
[(1, 2), (2, 3), (3, 4)]

Edgelist with data in Python dictionary representation:

>>> lines = ["1 2 {'weight': 3}", "2 3 {'weight': 27}", "3 4 {'weight': 3.0}"]
>>> G = eg.parse_edgelist(lines, nodetype=int)
>>> list(G)
[1, 2, 3, 4]
>>> list(G.edges)
[(1, 2, {'weight': 3}), (2, 3, {'weight': 27}), (3, 4, {'weight': 3.0})]

Edgelist with data in a list:

>>> lines = ["1 2 3", "2 3 27", "3 4 3.0"]
>>> G = eg.parse_edgelist(lines, nodetype=int, data=(("weight", float),))
>>> list(G)
[1, 2, 3, 4]
>>> list(G.edges)
[(1, 2, {'weight': 3.0}), (2, 3, {'weight': 27.0}), (3, 4, {'weight': 3.0})]

See also

read_weighted_edgelist

easygraph.readwrite.edgelist.read_edgelist(path, comments='#', delimiter=None, create_using=None, nodetype=None, data=True, edgetype=None, encoding='utf-8')[source]#

Read a graph from a list of edges.

Parameters:

  • path (file or string) – File or filename to read. If a file is provided, it must be opened in ‘rb’ mode. Filenames ending in .gz or .bz2 will be uncompressed.

  • comments (string, optional) – The character used to indicate the start of a comment. To specify that no character should be treated as a comment, use comments=None.

  • delimiter (string, optional) – The string used to separate values. The default is whitespace.

  • create_using (EasyGraph graph constructor, optional (default=eg.Graph)) – Graph type to create. If graph instance, then cleared before populated.

  • nodetype (int, float, str, Python type, optional) – Convert node data from strings to specified type

  • data (bool or list of (label,type) tuples) – Tuples specifying dictionary key names and types for edge data

  • edgetype (int, float, str, Python type, optional OBSOLETE) – Convert edge data from strings to specified type and use as ‘weight’

  • encoding (string, optional) – Specify which encoding to use when reading file.

Returns:

G – A easygraph Graph or other type specified with create_using

Return type:

graph

Examples

>>> eg.write_edgelist(eg.path_graph(4), "test.edgelist")
>>> G = eg.read_edgelist("test.edgelist")

>>> fh = open("test.edgelist", "rb")
>>> G = eg.read_edgelist(fh)
>>> fh.close()

>>> G = eg.read_edgelist("test.edgelist", nodetype=int)
>>> G = eg.read_edgelist("test.edgelist", create_using=eg.DiGraph)

Edgelist with data in a list:

>>> textline = "1 2 3"
>>> fh = open("test.edgelist", "w")
>>> d = fh.write(textline)
>>> fh.close()
>>> G = eg.read_edgelist("test.edgelist", nodetype=int, data=(("weight", float),))
>>> list(G)
[1, 2]
>>> list(G.edges)
[(1, 2, {'weight': 3.0})]

See parse_edgelist() for more examples of formatting.

See also

parse_edgelist, write_edgelist

Notes

Since nodes must be hashable, the function nodetype must return hashable types (e.g. int, float, str, frozenset - or tuples of those, etc.)

easygraph.readwrite.edgelist.read_weighted_edgelist(path, comments='#', delimiter=None, create_using=None, nodetype=None, encoding='utf-8')[source]#

Read a graph as list of edges with numeric weights.

Parameters:

  • path (file or string) – File or filename to read. If a file is provided, it must be opened in ‘rb’ mode. Filenames ending in .gz or .bz2 will be uncompressed.

  • comments (string, optional) – The character used to indicate the start of a comment.

  • delimiter (string, optional) – The string used to separate values. The default is whitespace.

  • create_using (EasyGraph graph constructor, optional (default=eg.Graph)) – Graph type to create. If graph instance, then cleared before populated.

  • nodetype (int, float, str, Python type, optional) – Convert node data from strings to specified type

  • encoding (string, optional) – Specify which encoding to use when reading file.

Returns:

G – A easygraph Graph or other type specified with create_using

Return type:

graph

Notes

Since nodes must be hashable, the function nodetype must return hashable types (e.g. int, float, str, frozenset - or tuples of those, etc.)

Example edgelist file format.

With numeric edge data:

# read with
# >>> G=eg.read_weighted_edgelist(fh)
# source target data
a b 1
a c 3.14159
d e 42

See also

write_weighted_edgelist

easygraph.readwrite.edgelist.write_edgelist(G, path, comments='#', delimiter=' ', data=True, encoding='utf-8')[source]#

Write graph as a list of edges.

Parameters:

  • G (graph) – A EasyGraph graph

  • path (file or string) – File or filename to write. If a file is provided, it must be opened in ‘wb’ mode. Filenames ending in .gz or .bz2 will be compressed.

  • comments (string, optional) – The character used to indicate the start of a comment

  • delimiter (string, optional) – The string used to separate values. The default is whitespace.

  • data (bool or list, optional) – If False write no edge data. If True write a string representation of the edge data dictionary.. If a list (or other iterable) is provided, write the keys specified in the list.

  • encoding (string, optional) – Specify which encoding to use when writing file.

Examples

>>> G = eg.path_graph(4)
>>> eg.write_edgelist(G, "test.edgelist")
>>> G = eg.path_graph(4)
>>> fh = open("test.edgelist", "wb")
>>> eg.write_edgelist(G, fh)
>>> eg.write_edgelist(G, "test.edgelist.gz")
>>> eg.write_edgelist(G, "test.edgelist.gz", data=False)

>>> G = eg.Graph()
>>> G.add_edge(1, 2, weight=7, color="red")
>>> eg.write_edgelist(G, "test.edgelist", data=False)
>>> eg.write_edgelist(G, "test.edgelist", data=["color"])
>>> eg.write_edgelist(G, "test.edgelist", data=["color", "weight"])

See also

read_edgelist, write_weighted_edgelist

easygraph.readwrite.edgelist.write_weighted_edgelist(G, path, comments='#', delimiter=' ', encoding='utf-8')[source]#

Write graph G as a list of edges with numeric weights.

Parameters:

  • G (graph) – A EasyGraph graph

  • path (file or string) – File or filename to write. If a file is provided, it must be opened in ‘wb’ mode. Filenames ending in .gz or .bz2 will be compressed.

  • comments (string, optional) – The character used to indicate the start of a comment

  • delimiter (string, optional) – The string used to separate values. The default is whitespace.

  • encoding (string, optional) – Specify which encoding to use when writing file.

Examples

>>> G = eg.Graph()
>>> G.add_edge(1, 2, weight=7)
>>> eg.write_weighted_edgelist(G, "test.weighted.edgelist")

See also

read_edgelist, write_edgelist, read_weighted_edgelist