> setwd("path-to-favDir") > library(network) > myEdges <- read.table("edges.txt", header=T)We now look at the lines 500 to 600 in the table and create a network from these lines:
> myEdges[500:600,] > network <- network(myEdges[500:600,])In this part of the table, there are exactly 101 edges, all with the same source node with ID 1 and 101 other nodes. Thus, we would expect that the resulting network has 102 nodes. So, let's check:
> network.size(network) > 568So, essentially what happens is that the network()-function creates a node for each ID from 1 until the maximum ID of 568. This is a (bug or feature?) side-effect of the IDs being numeric, i.e., of type int in the data.frame myEdges. If you again tell R to read in the nodes' IDs as characters, the resulting network will have the expected 102 nodes:
> myEdges <- read.table("edges.txt", header=T, colClasses=c("character", "character")) > network2 <- network(myEdges[500:600,]) > network.size(network2) > 102
So, if you ever experience long transformation times from data.frame to network, check whether your IDs have a numeric type and whether you have IDs which are much higher than the number of nodes in the network.