Return the number of nodes of the graph with degree equal to 1.
A vertex with degree equal to 1 is also called a leaf.
Parameters: G (NetworkX graph) – An undirected graph. Returns: The number of nodes in the graph with degree equal to 1. Return type: int
>>> G = nx.path_graph(3) # Path on 3 nodes >>> nx.number_of_leaves(G) 2