chat-message-matrix-factory.R

library(tm)
library(RWeka)

CreateChatMessagesMatrix <-
    function(messages.corpus, terms = NULL) {
        DocumentTermMatrix(
            messages.corpus,
            control = list(
                tokenizer = WordTokenizer,
                weighting = weightTf,
                wordLengths = c(1, Inf),
                dictionary = terms
            )
        )
    }

GetKnownTermsLevel <- function(messages.corpus, known.terms) {
    messages.matrix <- CreateChatMessagesMatrix(messages.corpus)
    messages.matrix.terms <- Terms(messages.matrix)
    if (length(messages.matrix.terms) > 0) {
        length(intersect(messages.matrix.terms, known.terms)) / length(messages.matrix.terms)
    } else {
        1
    }
}