Counting Hashtag Usage with R

Found this on the Revolution Analytics blog: What does Barack Obama tweet about most? In essence, pull down all the tweets from the official Twitter feed for the President, grab the hashtags and create a bar graph.

I don't often use R interactively. I generally make a script, set it in crontab, and have it run automatically. So, I adapted it to run via Rscript.

	#!/usr/bin/Rscript
	# Adapted from http://decisionsandr.blogspot.com/2013/11/using-r-to-find-obamas-most-frequent.html
	# As Seen on http://blog.revolutionanalytics.com/2013/11/what-does-barack-obama-tweet-about-most.html
	# I often run this sort of thing via command-line, so I use Cairo
	# so I can make images without X11
	# Usage
	# hashtags.rs <TwitterHandle>
	# ----------------------------------------------------------------------
	# Libraries
	library( twitteR )
	library( ggplot2 )
	library( Cairo )
	# ----------------------------------------------------------------------
	# Arguments
	args <- commandArgs(trailingOnly = TRUE)
	user <- ""
	if ( length(args) > 0 ) {
	user <- args[1]
	} else {
	print( "No user set. Exiting." )
	quit()
	}
	# ----------------------------------------------------------------------
	# Authentication and Configuration
	load("~/twitter-cred.Rd") # created with getTwitterOAuth
	registerTwitterOAuth(cred)
	NumberOfTweets <- 3200 #choose number of tweets to download
	NumberOfBars <- 20 # plot the top N hashtags by frequency
	# ----------------------------------------------------------------------
	# Functions
	extract.hashes = function(vec){
	hash.pattern = "#[[:alnum:]]+" # alnum to allow numerals
	have.hash = grep(x = vec, pattern = hash.pattern)
	hash.matches = gregexpr(pattern = hash.pattern,
	text = vec[have.hash])
	extracted.hash = regmatches(x = vec[have.hash], m = hash.matches)
	df = data.frame(table(tolower(unlist(extracted.hash))))
	colnames(df) = c("tag","freq")
	df = df[order(df$freq,decreasing = TRUE),]
	return(df)
	}
	# ----------------------------------------------------------------------
	# Get and Handle Data
	tw = userTimeline(user, n = NumberOfTweets)
	tw = twListToDF(tw)
	vec1 = tw$text
	dat = head(extract.hashes(vec1), NumberOfBars)
	dat2 = transform(dat,tag = reorder(tag,freq))
	# ----------------------------------------------------------------------
	# Make Plot
	file <- paste(
	'/home/jacoby/twitter-hash-' , user , '.png' ,
	sep = '' ,collapse = '' ) # do better
	CairoPNG(
	filename = file ,
	width = 600 ,
	height = 400 ,
	pointsize = 12
	)
	ggplot(
	dat2,
	aes(x = tag, y = freq)
	) +
	geom_bar(
	fill = "blue" ,
	stat = "identity" # fixes warning bug about stat="bin"
	) +
	coord_flip() +
	labs(
	title = paste("Hashtag frequencies in the tweets of @",user,sep="")
	)

view raw hashtags.rs hosted with ❤ by GitHub