Twitter Sentiment Analysis

twitter_SA.R

library(twitteR)
library(ROAuth)
library(ggplot2)


kejriwal.list <- searchTwitter('#kejriwal', n=1000)

#twListToDF() will take a list of objects from a single twitteR class and return a data.frame version of the members
kejriwal.df =twListToDF(kejriwal.list)
write.csv(kejriwal.df, file='c:/test/kejriwal.csv', row.names=F)


library(plyr)
library(stringr)
#The sentiment analysis uses two packages plyr and stringr to manipulate strings. 

score.sentiment= function(sentence, pos.words, neg.words, .progress='none')
{
  require(plyr)
  require(stringr)
  
  scores= laply(sentence, function(sentence, pos.words, neg.words){
    sentence = gsub('[[:punct:]]', '', sentence)
    sentence = gsub('[[:cntrl:]]', '', sentence)
    sentence = gsub('\\d+', '', sentence)
    
    sentence = tolower(sentence)
    
    word.list = str_split(sentence, '\\s+')
    
    words = unlist(word.list)
    
    pos.matches = match(words, pos.words)
    neg.matches = match(words, neg.words)
    
    pos.matches = !is.na(pos.matches)
    neg.matches = !is.na(neg.matches)
    
    score = sum(pos.matches) - sum(neg.matches)
    return(score)
  }, pos.words, neg.words, .progress=.progress)
  scores.df = data.frame(score=scores, text=sentence)
  return(scores.df)
}

#scoring tweets and adding column
hu.liu.pos = scan('c:/test/positive-words.txt', what='character', comment.char = ';')
hu.liu.neg = scan('c:/test/negative-words.txt', what='character', comment.char = ';')

pos.words = c(hu.liu.pos, 'upgrade')
neg.words = c(hu.liu.neg, 'wtf', 'wait', 'waiting', 'epicfail', 'mechanical')


#import the csv file
DatasetKejriwal <- read.csv("C:/test/kejriwal.csv")
DatasetKejriwal$text <- as.factor(DatasetKejriwal$text)

#score all tweets
kejriwal.scores = score.sentiment(DatasetKejriwal$text, pos.words, neg.words, .progress = 'text')
path <- "c:/test/"
write.csv(kejriwal.scores, file=paste(path, "kejriwalScores.csv", sep=""), row.names=TRUE)
View(kejriwal.scores)

#Visualizing the tweets

hist(kejriwal.scores$score, xlab="Score of Tweets", col="red")

qplot(kejriwal.scores$score, xlab = "Score of Tweets")