summarization.graph – Graph used in TextRank summarization¶
This module contains abstract class IGraph represents graphs interface and class Graph (based on IGraph) which implements undirected graph.
Examples
Create simple graph with 4 nodes.
>>> g = Graph()
>>> g.add_node('Felidae')
>>> g.add_node('Lion')
>>> g.add_node('Tiger')
>>> g.add_node('Wolf')
>>> sorted(g.nodes())
['Felidae', 'Lion', 'Tiger', 'Wolf']
Add some edges and check neighbours.
>>> g.add_edge(("Felidae", "Lion"))
>>> g.add_edge(("Felidae", "Tiger"))
>>> g.neighbors("Felidae")
['Lion', 'Tiger']
One node has no neighbours.
>>> g.neighbors("Wolf")
[]
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class
gensim.summarization.graph.Graph¶ Implementation of an undirected graph, based on IGraph.
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DEFAULT_WEIGHT¶ Weight set by default.
- Type
float
Initializes object.
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DEFAULT_WEIGHT= 0
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add_edge(edge, wt=1)¶ Adds an edge to the graph connecting two nodes.
- Parameters
edge ((hashable, hashable)) – Given edge.
wt (float, optional) – Weight of new edge.
- Raises
ValueError – If edge already exists in graph.
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add_node(node)¶ Adds given node to the graph.
Note
While nodes can be of any type, it’s strongly recommended to use only numbers and single-line strings as node identifiers if you intend to use write().
- Parameters
node (hashable) – Given node.
- Raises
ValueError – If node already exists in graph.
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del_edge(edge)¶ Removes given edges from the graph.
- Parameters
edge ((hashable, hashable)) – Given edge.
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del_node(node)¶ Removes given node and its edges from the graph.
- Parameters
node (hashable) – Given node.
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edge_weight(edge)¶ Returns weight of given edge.
- Parameters
edge ((hashable, hashable)) – Given edge.
- Returns
Edge weight.
- Return type
float
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edges()¶ Returns all edges of the graph.
- Returns
Edges of graph.
- Return type
list of (hashable, hashable)
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has_edge(edge)¶ Returns whether an edge exists.
- Parameters
edge ((hashable, hashable)) – Given edge.
- Returns
True if edge exists, False otherwise.
- Return type
bool
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has_node(node)¶ Returns whether the requested node exists.
- Parameters
node (hashable) – Given node.
- Returns
True if node exists, False otherwise.
- Return type
bool
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iter_edges()¶ Returns iterator of all edges of the graph.
- Yields
(hashable, hashable) – Edges of graph.
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neighbors(node)¶ Returns all nodes that are directly accessible from given node.
- Parameters
node (hashable) – Given node identifier.
- Returns
Nodes directly accessible from given node.
- Return type
list of hashable
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nodes()¶ Returns all nodes of the graph.
- Returns
Nodes of graph.
- Return type
list of hashable
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class
gensim.summarization.graph.IGraph¶ Represents the interface or contract that the graph for TextRank should implement.
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abstract
add_edge(edge, wt=1)¶ Adds an edge to the graph connecting two nodes. An edge, here, is a tuple of two nodes.
- Parameters
edge ((hashable, hashable)) – Given edge.
wt (float, optional) – Weight of new edge.
-
abstract
add_node(node)¶ Adds given node to the graph.
Note
While nodes can be of any type, it’s strongly recommended to use only numbers and single-line strings as node identifiers if you intend to use write().
- Parameters
node (hashable) – Given node
-
abstract
del_node(node)¶ Removes node and its edges from the graph.
- Parameters
node (hashable) – Node to delete.
-
abstract
edge_weight(edge)¶ Returns weigth of given edge.
- Parameters
edge ((hashable, hashable)) – Given edge.
- Returns
Edge weight.
- Return type
float
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abstract
edges()¶ Returns all edges of graph.
- Returns
Edges of graph.
- Return type
list of (hashable, hashable)
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abstract
has_edge(edge)¶ Returns whether an edge exists.
- Parameters
edge ((hashable, hashable)) – Given edge.
- Returns
True if edge exists, False otherwise.
- Return type
bool
-
abstract
has_node(node)¶ Returns whether the requested node exists.
- Parameters
node (hashable) – Given node identifier.
- Returns
True if node exists, False otherwise.
- Return type
bool
-
abstract
neighbors(node)¶ Return all nodes that are directly accessible from given node.
- Parameters
node (hashable) – Given node identifier.
- Returns
Nodes directly accessible from given node.
- Return type
list of hashable
-
abstract
nodes()¶ Returns all nodes of graph.
- Returns
Nodes of graph.
- Return type
list of hashable
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abstract