network-overview.R

# pull twitter package from repo
install.packages('devtools')
library('devtools')
install_github("twitteR", username="geoffjentry")
library('twitteR')
setup_twitter_oauth(YOUR CREDENTIALS HERE, credentials_file=NULL)

# set up igraph
install.packages('igraph')
library('igraph')

# set up some data; i hate the <- operator
me = getUser('eegilbert')
# set to 200 to avoid traversing lots of pages and eating up api
N = 200
# also look at ids, if you don't care about screen names
ifollow = me$getFriends(n=N)
ifollow = twListToDF(ifollow)
ifollow = ifollow$screenName

# convert to adj matrix
adj = matrix(nrow=N, ncol=N)
rownames(adj) = ifollow
colnames(adj) = ifollow
adj[] = 0

for (theirname in ifollow) {
  # back off if we're out of api; this loop can take hours
  apileft = getCurRateLimitInfo(c("friends"))$remaining[1]
  if (as.numeric(apileft) <= 0) { Sys.sleep(15*60+30) }
  them = getUser(theirname)
  theyfollow = them$getFriends(n=N)
  theyfollow = twListToDF(theyfollow)
  theyfollow = theyfollow$screenName
  alsofollow = intersect(ifollow, theyfollow)
  for (mutualname in alsofollow) {
    adj[theirname, mutualname] = 1
  }
  print(paste("done with", theirname))
}

# set up graph
g = graph.adjacency(adj, mode = "directed", add.rownames=T)
# may want to play with filtering nodes to better visualize, as below
g = delete.vertices(g, which(degree(g)<10))
V(g)$label <- V(g)$name
V(g)$degree <- degree(g)

# make it look a little better
V(g)$label.cex = 2.2 * V(g)$degree / max(V(g)$degree)+ .2
V(g)$label.color = rgb(0, 0, .2, .8)

# basic viz
plot(g, layout=layout.auto(g))

diameter(g)

# random walk community detection
communities = walktrap.community(g)
# how many communities
length(communities)
# draw them on the graph
plot(communities, g)

# rank people by different centralities
cm = cbind(V(g), betweenness(g))
cm[sort.list(cm[,2], decreasing=T),]

cm = cbind(V(g), page.rank(g)$vector)
cm[sort.list(cm[,2], decreasing=T),]

# look to burt
sort(constraint(g))