Class VertexSeq

Shorthand notation to select()

This method simply passes all its arguments to VertexSeq.select().

Proxy method to Graph.betweenness()

This method calls the betweenness() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.bibcoupling()

This method calls the bibcoupling() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.closeness()

This method calls the closeness() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.cocitation()

This method calls the cocitation() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.constraint()

This method calls the constraint() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.degree()

This method calls the degree() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.eccentricity()

This method calls the eccentricity() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.get_shortest_paths()

This method calls the get_shortest_paths() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.indegree()

This method calls the indegree() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.isoclass()

This method calls the isoclass() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.maxdegree()

This method calls the maxdegree() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.outdegree()

This method calls the outdegree() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.pagerank()

This method calls the pagerank() method of the Graph class restricted to this sequence, and returns the result.

Selects a subset of the vertex sequence based on some criteria

The selection criteria can be specified by the positional and the keyword arguments. Positional arguments are always processed before keyword arguments.

• If the first positional argument is None, an empty sequence is returned.
• If the first positional argument is a callable object, the object will be called for every vertex in the sequence. If it returns True, the vertex will be included, otherwise it will be excluded.
• If the first positional argument is an iterable, it must return integers and they will be considered as indices of the current vertex set (NOT the whole vertex set of the graph -- the difference matters when one filters a vertex set that has already been filtered by a previous invocation of VertexSeq.select(). In this case, the indices do not refer directly to the vertices of the graph but to the elements of the filtered vertex sequence.
• If the first positional argument is an integer, all remaining arguments are expected to be integers. They are considered as indices of the current vertex set again.

Keyword arguments can be used to filter the vertices based on their attributes. The name of the keyword specifies the name of the attribute and the filtering operator, they should be concatenated by an underscore (_) character. Attribute names can also contain underscores, but operator names don't, so the operator is always the largest trailing substring of the keyword name that does not contain an underscore. Possible operators are:

• eq: equal to
• ne: not equal to
• lt: less than
• gt: greater than
• le: less than or equal to
• ge: greater than or equal to
• in: checks if the value of an attribute is in a given list
• notin: checks if the value of an attribute is not in a given list

For instance, if you want to filter vertices with a numeric age property larger than 200, you have to write:

>>> g.vs.select(age_gt=200)

Similarly, to filter vertices whose type is in a list of predefined types:

>>> list_of_types = ["HR", "Finance", "Management"]
>>> g.vs.select(type_in=list_of_types)

If the operator is omitted, it defaults to eq. For instance, the following selector selects vertices whose cluster property equals to 2:

>>> g.vs.select(cluster=2)

In the case of an unknown operator, it is assumed that the recognized operator is part of the attribute name and the actual operator is eq.

Attribute names inferred from keyword arguments are treated specially if they start with an underscore (_). These are not real attributes but refer to specific properties of the vertices, e.g., its degree. The rule is as follows: if an attribute name starts with an underscore, the rest of the name is interpreted as a method of the Graph object. This method is called with the vertex sequence as its first argument (all others left at default values) and vertices are filtered according to the value returned by the method. For instance, if you want to exclude isolated vertices:

>>> non_isolated = g.vs.select(_degree_gt=0)

For properties that take a long time to be computed (e.g., betweenness centrality for large graphs), it is advised to calculate the values in advance and store it in a graph attribute. The same applies when you are selecting based on the same property more than once in the same select() call to avoid calculating it twice unnecessarily. For instance, the following would calculate betweenness centralities twice:

>>> g.vs.select(_betweenness_gt=10, _betweenness_lt=30)

It is advised to use this instead:

>>> g.vs["bs"] = g.betwenness()
>>> g.vs.select(bs_gt=10, bs_lt=30)

Returns: VertexSeq

the new, filtered vertex sequence

Overrides: core.VertexSeq.select

Proxy method to Graph.shortest_paths()

This method calls the shortest_paths() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.similarity_dice()

This method calls the similarity_dice() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.similarity_jaccard()

This method calls the similarity_jaccard() method of the Graph class restricted to this sequence, and returns the result.

Proxy method to Graph.subgraph()

This method calls the subgraph() method of the Graph class restricted to this sequence, and returns the result.