|igraph Reference Manual|
Everything about vertices and vertex selectors also applies to edges and edge selectors unless explicitly noted otherwise.
The vertex (and edge) selector notion was introduced in igraph 0.2, and it is a way to reference to sequence of vertices or edges independently of the graph.
While this might sound quite mysterious, it is actually very
simple. For example all vertex of graph can be selected by
igraph_vs_all(), and the graph independence means that
igraph_vs_all() is not parametrized by a graph object. Ie.
igraph_vs_all() is the concept of selecting all vertices
of a graph.
This means that for determining the actual vertex id's implied by a vertex selector it needs to be instantiated with a graph object, the instantiation results a vertex iterator.
Some vertex selectors have immediate versions, these have
igraph_vss instead of
igraph_vs , eg.
igraph_vss_all() instead of
These immediate versions are to be used in the parameter list of the igraph
igraph_degree(). These functions are not
associated with any igraph_vs_t object, so they have no
separate constructors and destructors (destroy functions).
|<< Chapter 8. Vertex and Edge Selectors and Sequences, Iterators||2. Vertex selector constructors >>|