install.packages("tm.lexicon.GeneralInquirer", repos="http://datacube.wu.ac.at", type="source") library(tm.lexicon.GeneralInquirer) install.packages("tm.plugin.sentiment", repos="http://R-Forge.R-project.org") #library(tm.plugin.sentiment) library(tm) sentiment_analysis<-function(some_txt){ corpus<-Corpus(VectorSource(some_txt)) pos<-sum(sapply(corpus,tm_term_score,terms_in_General_Inquirer_categories("Positiv"))) neg<-sum(sapply(corpus,tm_term_score,terms_in_General_Inquirer_categories("Negativ"))) pos.score<-tm_term_score(TermDocumentMatrix(corpus,control=list(removePunctuation=TRUE)),terms_in_General_Inquirer_categories("Positiv")) neg.score<-tm_term_score(TermDocumentMatrix(corpus,control=list(removePunctuation=TRUE)),terms_in_General_Inquirer_categories("Negativ")) total.df<-data.frame(positive=pos.score,negative=neg.score) total.df<-transform(total.df,net=positive-negative) total.df }