tf-idf

作者: 一筐_8dc5 | 来源:发表于2020-09-20 15:42 被阅读0次

tf-idf:词频-逆向文档频率


TF_{w,D_{i} }=\frac{count(w)}{|D_{i} |}

{IDF}_w=log\frac{N}{\sum\nolimits_{i=1}^NI(w,{D}_i) },I(w,{D}_i)表示文档是否包含w词


```

#coding=utf-8

import os

import jieba

from sklearn.feature_extraction.text import CountVectorizer, TfidfTransformer

import numpy as np

def splitChapter():

   """

   只拆分第一本书的73章作为数据,编码utf-8

   :return:

   """

   with open("./冰与火之歌_乔治·马丁utf8.txt",encoding="utf-8") as f:

      lines=f.readlines()

   length = len(lines)

   title = None

   f = open("标题作者.txt", "w", encoding="utf-8")

   n = 0

   for i in range(length):

      if lines[i][0]=="第":

         n+=1

         title = lines[i].strip()

         f.close()

         f = open(str(n)+title+".txt", "w", encoding="utf-8")

         f.write(lines[i])

      else:

         f.write(lines[i])

def wordslist():

   """

   分词

   :return:

   """

   # wordList = []

   stop_word = [line.rstrip() for line in open("./stopwords.txt", encoding="utf-8")]

   jieba.add_word(u"丹妮莉丝")

   jieba.add_word(u"提利昂")

   # fr = open("测试.txt", "a", encoding="utf-8")

   for file in os.listdir("./data")[1:-2]:

      with open("./data/"+file, "r", encoding="utf-8") as f:

         content = f.read().strip().replace("\n", "").replace(" ", "").replace("\t", "").replace("\r", "")

      seg_list = jieba.cut(content, cut_all=True)

      seg_list_after = []

      # 去停用词

      for seg in seg_list:

         if seg not in stop_word:

            seg_list_after.append(seg)

      result = " ".join(seg_list_after)

      # wordList.append(result)

      yield result

      # fr.write(result+"\n")

   # fr.close()

def titlelist():

   for file in os.listdir("./data")[1:-2]:

      yield file

if __name__ == '__main__':

   wordslist = list(wordslist())

   titlelist = list(titlelist())

   # 计算每个text中的词频

   vectorizer = CountVectorizer()

   x = vectorizer.fit_transform(wordslist)

   # print(vectorizer.get_feature_names())

   # print(x.toarray())

   # 计算tf-idf

   transformer = TfidfTransformer()

   tfidf = transformer.fit_transform(x)

   # 所有文本中的关键词

   words = vectorizer.get_feature_names()

   # 所有文本中词的权重

   weights = tfidf.toarray()

   n = 5

   for (title, w) in zip(titlelist, weights):

      print(u"{}:".format(title))

      loc = np.argsort(-w) # 排序 倒排!!!

      for i in range(n):

         print(u"-{}:{} {}".format(str(i+1), words[loc[i]], w[loc[i]]))

      print("\n")

```

相关文章

网友评论

      本文标题:tf-idf

      本文链接:https://www.haomeiwen.com/subject/xwfpyktx.html