Visualize Retweets with R

Hi there!

Today I want to show you how to plot a graph filled with Data of Retweets of a Twitter Account.

To start you have to go through the Twitter authentification process as i described in an earlier blog post you can find here.

Let´s get started with the things we are really interested in.

Get the data

To start the data mining we need to load 3 packages.

library(twitteR)
library(igraph)
library(stringr)

To get the posts of a certain user, the twitteR package provides a cool function

tweets = userTimeline("mashable", n=1000)

This gets us around 1000 tweets from the user account @mashable. These are saved in the Variable tweets and we can extract the text in the next step with

tweet_txt = sapply(tweets, function(x) x$getText())

But now we have to recognize the retweets in this huge amount of text.

# regular expressions to find retweets
grep("(RT|via)((?:\\b\\W*@\\w+)+)", tweets,
ignore.case=TRUE, value=TRUE)

# which tweets are retweets
rt_patterns = grep("(RT|via)((?:\\b\\W*@\\w+)+)",
tweet_txt, ignore.case=TRUE)

# show retweets (these are the ones we want to focus on)
tweet_txt[rt_patterns] 

Now that we have our raw data we can go on analyzing it.

Analyzing the data

# we create a list to store user names
who_retweet = as.list(1:length(rt_patterns))
who_post = as.list(1:length(rt_patterns))

# for loop
for (i in 1:length(rt_patterns))
{
 # get tweet with retweet entity
 twit = tweets[[rt_patterns[i]]]
 # get retweet source
 poster = str_extract_all(twit$getText(),
 "(RT|via)((?:\\b\\W*@\\w+)+)")
 #remove ':'
 poster = gsub(":", "", unlist(poster))
 # name of retweeted user
 who_post[[i]] = gsub("(RT @|via @)", "", poster, ignore.case=TRUE)
 # name of retweeting user
 who_retweet[[i]] = rep(twit$getScreenName(), length(poster))
}

# and we put it off the list
who_post = unlist(who_post)
who_retweet = unlist(who_retweet)

Now we have created our so called edge list. A list which shows the connections of our data. A very common construct in R.
But our goal wasn´t an edge list, but a graph. So we have to form our edge list in a nice graph.

# two column matrix of edges
retweeter_poster = cbind(who_retweet, who_post)

# generate graph
rt_graph = graph.edgelist(retweeter_poster)

# get vertex names
ver_labs = get.vertex.attribute(rt_graph, "name", index=V(rt_graph))

Now there are just a few steps left to see our retweet graph.

# choose some layout
glay = layout.fruchterman.reingold(rt_graph)

# plot
par(bg="gray15", mar=c(1,1,1,1))
plot(rt_graph, layout=glay,
 vertex.color="gray25",
 vertex.size=10,
 vertex.label=ver_labs,
 vertex.label.family="sans",
 vertex.shape="none",
 vertex.label.color=hsv(h=0, s=0, v=.95, alpha=0.5),
 vertex.label.cex=0.85,
 edge.arrow.size=0.8,
 edge.arrow.width=0.5,
 edge.width=3,
 edge.color=hsv(h=.95, s=1, v=.7, alpha=0.5))
# add title
title("\nTweets from the User account @mashable: Who retweets whom",
 cex.main=1, col.main="gray95")

And here it is:
Our nice retweets graph!