easygraph.classes.operation module#

easygraph.classes.operation.add_path(G_to_add_to, nodes_for_path, **attr)[source]#

Add a path to the Graph G_to_add_to.

Parameters:

G_to_add_to (graph) – A EasyGraph graph
nodes_for_path (iterable container) – A container of nodes. A path will be constructed from the nodes (in order) and added to the graph.
attr (keyword arguments, optional (default= no attributes)) – Attributes to add to every edge in path.

See also

nodes_with_selfloops, number_of_selfloops

Examples

>>> G = eg.MultiGraph()  # or Graph, DiGraph, MultiDiGraph, etc
>>> ekey = G.add_edge(1, 1)
>>> ekey = G.add_edge(1, 2)
>>> list(eg.selfloop_edges(G))
[(1, 1)]
>>> list(eg.selfloop_edges(G, data=True))
[(1, 1, {})]
>>> list(eg.selfloop_edges(G, keys=True))
[(1, 1, 0)]
>>> list(eg.selfloop_edges(G, keys=True, data=True))
[(1, 1, 0, {})]

easygraph.classes.operation.set_edge_attributes(G, values, name=None)[source]#

Sets edge attributes from a given value or dictionary of values.

Warning

The call order of arguments values and name switched between v1.x & v2.x.

Parameters:

G (EasyGraph Graph) –
values (scalar value, dict-like) –
What the edge attribute should be set to. If values is not a dictionary, then it is treated as a single attribute value that is then applied to every edge in G. This means that if you provide a mutable object, like a list, updates to that object will be reflected in the edge attribute for each edge. The attribute name will be name.

If values is a dict or a dict of dict, it should be keyed by edge tuple to either an attribute value or a dict of attribute key/value pairs used to update the edge’s attributes. For multigraphs, the edge tuples must be of the form (u, v, key), where u and v are nodes and key is the edge key. For non-multigraphs, the keys must be tuples of the form (u, v).
name (string (optional, default=None)) – Name of the edge attribute to set if values is a scalar.

Examples

After computing some property of the edges of a graph, you may want to assign a edge attribute to store the value of that property for each edge:

>>> G = eg.path_graph(3)
>>> bb = eg.edge_betweenness_centrality(G, normalized=False)
>>> eg.set_edge_attributes(G, bb, "betweenness")
>>> G.edges[1, 2]["betweenness"]
2.0

If you provide a list as the second argument, updates to the list will be reflected in the edge attribute for each edge:

>>> labels = []
>>> eg.set_edge_attributes(G, labels, "labels")
>>> labels.append("foo")
>>> G.edges[0, 1]["labels"]
['foo']
>>> G.edges[1, 2]["labels"]
['foo']

If you provide a dictionary of dictionaries as the second argument, the entire dictionary will be used to update edge attributes:

>>> G = eg.path_graph(3)
>>> attrs = {(0, 1): {"attr1": 20, "attr2": "nothing"}, (1, 2): {"attr2": 3}}
>>> eg.set_edge_attributes(G, attrs)
>>> G[0][1]["attr1"]
20
>>> G[0][1]["attr2"]
'nothing'
>>> G[1][2]["attr2"]
3

Note that if the dict contains edges that are not in G, they are silently ignored:

>>> G = eg.Graph([(0, 1)])
>>> eg.set_edge_attributes(G, {(1, 2): {"weight": 2.0}})
>>> (1, 2) in G.edges()
False

easygraph.classes.operation.set_node_attributes(G, values, name=None)[source]#

Sets node attributes from a given value or dictionary of values.

Warning

The call order of arguments values and name switched between v1.x & v2.x.

Parameters:

G (EasyGraph Graph) –
values (scalar value, dict-like) –
What the node attribute should be set to. If values is not a dictionary, then it is treated as a single attribute value that is then applied to every node in G. This means that if you provide a mutable object, like a list, updates to that object will be reflected in the node attribute for every node. The attribute name will be name.

If values is a dict or a dict of dict, it should be keyed by node to either an attribute value or a dict of attribute key/value pairs used to update the node’s attributes.
name (string (optional, default=None)) – Name of the node attribute to set if values is a scalar.

Examples

After computing some property of the nodes of a graph, you may want to assign a node attribute to store the value of that property for each node:

>>> G = eg.path_graph(3)
>>> bb = eg.betweenness_centrality(G)
>>> isinstance(bb, dict)
True
>>> eg.set_node_attributes(G, bb, "betweenness")
>>> G.nodes[1]["betweenness"]
1.0

If you provide a list as the second argument, updates to the list will be reflected in the node attribute for each node:

>>> G = eg.path_graph(3)
>>> labels = []
>>> eg.set_node_attributes(G, labels, "labels")
>>> labels.append("foo")
>>> G.nodes[0]["labels"]
['foo']
>>> G.nodes[1]["labels"]
['foo']
>>> G.nodes[2]["labels"]
['foo']

If you provide a dictionary of dictionaries as the second argument, the outer dictionary is assumed to be keyed by node to an inner dictionary of node attributes for that node:

>>> G = eg.path_graph(3)
>>> attrs = {0: {"attr1": 20, "attr2": "nothing"}, 1: {"attr2": 3}}
>>> eg.set_node_attributes(G, attrs)
>>> G.nodes[0]["attr1"]
20
>>> G.nodes[0]["attr2"]
'nothing'
>>> G.nodes[1]["attr2"]
3
>>> G.nodes[2]
{}

Note that if the dictionary contains nodes that are not in G, the values are silently ignored:

>>> G = eg.Graph()
>>> G.add_node(0)
>>> eg.set_node_attributes(G, {0: "red", 1: "blue"}, name="color")
>>> G.nodes[0]["color"]
'red'
>>> 1 in G.nodes
False

easygraph.classes.operation.topological_sort(G)[source]#