词云简介

使用 R 的 Bag-of-Words 进行文本挖掘

Ted Kwartler

Instructor

简单词云

# 将 TDM 转为矩阵
chardonnay_tdm <- TermDocumentMatrix(clean_chardonnay)
chardonnay_m <- as.matrix(chardonnay_tdm)


# 按词频汇总并排序
term_frequency <- rowSums(chardonnay_m)
word_freqs <- data.frame(term = names(term_frequency),
                         num = term_frequency)


# 生成词云
wordcloud(word_freqs$term, word_freqs$num, 
          max.words = 100, colors = "red")

词云.png

停用词的影响

clean_corpus <- function(corpus){
  corpus <- tm_map(corpus, removePunctuation)
  corpus <- tm_map(corpus, stripWhitespace)
  corpus <- tm_map(corpus, removeNumbers)
  corpus <- tm_map(corpus, 
                   content_transformer(tolower))
  corpus <- tm_map(corpus, removeWords, 
                   c(stopwords("en"), "amp"))
  return(corpus)
}

词云2.png

移除无信息词

clean_corpus <- function(corpus){
  corpus <- tm_map(corpus, removePunctuation)
  corpus <- tm_map(corpus, stripWhitespace)
  corpus <- tm_map(corpus, removeNumbers)
  corpus <- tm_map(corpus, 
                   content_transformer(tolower))

  corpus <- tm_map(corpus, removeWords, 
                   c(stopwords("en"), "amp", 
                    "chardonnay", "wine", "glass"))

  return(corpus)
}

词云3.png

让我们练习吧！

使用 R 的 Bag-of-Words 进行文本挖掘