Degree distribution

The degree of a node is the number of connections (links) with other nodes. In the case of directed graphs, each node has two degrees—the out-degree and the in-degree. In the undirected graph, the relationship is mutual; then we just have a single degree for each node. In the code listed here, we get the source node and target node references from the links.csv file. Then, we create a single list merging the two lists (target and source). Finally, we get a dictionary (dic) of how many times each node appears in the list, and we plot the result in a bar char using matplotlib.

The links.csv file will look like this:

edgedef>node1 VARCHAR,node2 VARCHAR 
23917067,35702006 
23917067,629395837 
23917067,747343482 
23917067,755605075 
23917067,1186286815 
.  .  . 
import numpy as np 
import matplotlib.pyplot as plt 
 
links = np.genfromtxt("links.csv", 
                       dtype=str, 
                       delimiter=',', 
                   ...