cache_node_count_ws: Cache a count of nodes (available in a selection)
in the graph
Description
From a graph object of class
dgr_graph, get a count of nodes available in
a selection and cache that value in the graph for
later retrieval using get_cache.
Usage
cache_node_count_ws(graph)
Arguments
graph
a graph object of class
dgr_graph that is created using
create_graph.