The igraph package for R is a wonderful tool that can be used to model networks, both real and virtual, with simplicity. This example is meant to demonstrate how to create two simple network graphs using the igraph package within R v.3.2.3.
The network is created with this piece of code:
g<-graph.formula(Node1-Node2, Node1-Node3, Node4-Node1) plot(g)
dg<-graph.formula(Tom-+Mary, Tom-+Bill, Tom-+Sam, Sue+-Mary, Bill-+Sue) plot(dg)
This code will then generate a network with arrows:
Code example of how to make a double sided arrow:
dg<-graph.formula(Tom-+Mary, Tom-+Bill, Tom-+Sam, Sue+-Mary, Bill++Sue) plot(dg)