第3章：中文本文向量化——代码详解

1.单条语句的向量化

根据不同的向量化，对“中华女子学院：本科层次仅1专业招男生”这句话进行向量化

1.1 One-hot方法

# one-hot代码
import jieba
import os
import numpy as np

stopwords = open('./data/哈工大停用词表.txt').read().split("\n")

words = '中华女子学院：本科层次仅1专业招男生'
word = jieba.lcut(words)
# print(word)
word = [w for w in word if w not in stopwords]  #去除停用词

one_hots = {}
lenth = len(word)
for index,word in enumerate(word):
    one_hot = [0]*lenth  #构造一个全为0的列表或者是一个一维矩阵
    one_hot[index] = 1
    one_hots[word] =one_hot 
print(one_hots)

1.2 TF和TF-IDF向量法

方法1：先使用CountVectorizer完成文本的TF表示，之后再使用TfidfTransformer完成文本的TF-IDF表示

# TF-IDF方法制作一句话的向量
import jieba
import os
import numpy as np

stopwords = open('./data/哈工大停用词表.txt').read().split("\n")
words = '中华女子学院：本科层次仅1专业招男生'
word = jieba.lcut(words)
word = [w for w in word if w not in stopwords]  #去除停用词

dic_data =[ " ".join(word)]
print(dic_data)
from sklearn.feature_extraction.text import CountVectorizer
vectorizer = CountVectorizer()
# 矩阵中包含一个元素a[i][j]，它表示j词在i类文本下的词频。它通过fit_transform函数计算各个词语出现的次数
count = vectorizer.fit_transform(dic_data)
# print(count)
from sklearn.feature_extraction.text import TfidfTransformer
transformer = TfidfTransformer() #类调用
tfidf = transformer.fit_transform(count) #将词频统计成TF-IDF值
#查看数据结构 tfidf[i][j]表示i类文本中的tf-idf权重
print(tfidf.toarray())

方法2：直接使用TfidfVectorizer完成文本的向量化

import jieba
import os
import numpy as np

stopwords = open('./data/哈工大停用词表.txt').read().split("\n")
words = '中华女子学院：本科层次仅1专业招男生'
word = jieba.lcut(words)
word = [w for w in word if w not in stopwords]  #去除停用词

dic_data =[ " ".join(word)]
print(dic_data)

from sklearn.feature_extraction.text import TfidfVectorizer
counttdidf = TfidfVectorizer()
count_tfidf = counttdidf.fit_transform(dic_data)
# print(count_tfidf)
train_weight = count_tfidf.toarray() #篇章(句)向量化 1800*dic
print(count_tfidf.toarray())

1.3 Word2Vec向量法

• 环境安装：pip install gensim
• 使用gensim进行Word2Vec进行向量化的数据格式为：[[‘中华’, ‘女子’, ‘学院’, ‘本科’, ‘层次’, ‘仅’, ‘1’, ‘专业’, ‘招’, ‘男生’], [‘两天’, ‘价’, ‘网站’, ‘背后’, ‘重重’, ‘迷雾’, ‘做个’, ‘网站’, ‘究竟’, ‘钱’], [‘东’, ‘5’, ‘环’, ‘海棠’, ‘公社’, ‘230’, ‘290’, ‘平’, ‘2’, ‘居’, ‘准现房’, ‘98’, ‘折’, ‘优惠’]]

from gensim.models import Word2Vec

stopwords = open('./data/哈工大停用词表.txt').read().split("\n")
words = '中华女子学院：本科层次仅1专业招男生'
word = jieba.lcut(words)
# print(word)
word = [[w for w in word if w not in stopwords]]  #去除停用词
# print(word)
#训练模型
model = Word2Vec(word, vector_size=5,min_count=1,epochs=7) #vector_size：向量表示的数量;min_count:最小统计的词；epochs：迭代次数,使得w1和w2更新的次数
#保存模型
model.save('model.bin')
# load model
new_model = Word2Vec.load('model.bin')
print(new_model.wv['学院'])
print("和学院相关性最高的前5个词：",model.wv.most_similar('学院',topn=5))

1.4 BERT向量法

• 环境配置
  1.python -V
  2.conda create -n pytorch python==3.7
  3.conda activate pytorch
  4.打开pytorch官网：https://pytorch.org/
  5.验证：
  import torch
  torch.version
  torch.cuda.is_available()
  6.pip install transformers

使用transformers进行向量化的数据格式为：['北京欢迎你','智能科学与技术']
"""
from transformers import BertTokenizer,BertModel
# 初始化分词器
tokenizer = BertTokenizer.from_pretrained('./bert_base_chinese')
#加载预训练模型
model = BertModel.from_pretrained('./bert_base_chinese')

batch_token1 = tokenizer(['北京欢迎你','智能科学与技术'],padding=True,return_tensors='pt') #padding=True：根据最长的句子进行填充；return_tensors='pt'：表示使用pytorch版本
print(batch_token1)

encoded = model(batch_token1['input_ids']) #有id转向量化过程
print(encoded) #last_hidden_state：词向量；pooler_output：分类的输出结果
encoded_text = encoded[0] #仅仅获得词向量
print('词向量:',encoded_text)
print("输出词向量的形状:",encoded_text.shape) #torch.Size([2, 9, 768]) 2个句子*9个词id*768

2.多条语句的向量化

语料说明：将3个文本保存在data.txt文档中，同时将data.txt文档存放在“练习data”这个文件夹当中。同时我们的代码是和该文件夹在同一目录中。

2.1 One-hot方法

# one-hot代码

import jieba
import os
import numpy as np

stopwords = open('./data/哈工大停用词表.txt').read().split("\n")

dic = []
with open('./练习data/data.txt','r',encoding='utf-8') as f:
    lines = f.read().split('\n')
    for line in lines:
        words = jieba.lcut(line)
        # for w in words:
        #     if w not in stopwords:
        #         dic.append(w)
        dic.append([w for w in words if w not in stopwords])
# print(dic)        
def mak_dic(seg_dic):
    dics = []
    for lines in seg_dic:
        for words in lines:
            if words not in dics:
                dics.append(words)
    print(len(dics))
         
    one_hots = {}
    lenth = len(dics)
    for index,word in enumerate(dics):
        print(word)
        one_hot = [0]*lenth  #构造一个全为0的列表或者是一个一维矩阵
        one_hot[index] = 1
        print(one_hot)
        one_hots[word] =one_hot
        
    return one_hots
result = mak_dic(dic)

2.2 TF-IDF方法

使用skearn进行TF-IDF进行向量化的数据格式为：['北京 欢迎 北京','你们 喜欢 北京','北京 天安门']
# TF-IDF方法
stopwords = open('./data/哈工大停用词表.txt').read().split("\n")

dic = []
dic_data = []
with open('./练习data/data.txt','r',encoding='utf-8') as f:
    lines = f.read().split('\n')
    for line in lines:
        words = jieba.lcut(line)
        # for w in words:
        #     if w not in stopwords:
        #         dic.append(w)
        dic.append([w for w in words if w not in stopwords])
        dic_datas = " ".join(words)
        dic_data.append(dic_datas)


from sklearn.feature_extraction.text import CountVectorizer
vectorizer = CountVectorizer()
# 矩阵中包含一个元素a[i][j]，它表示j词在i类文本下的词频。它通过fit_transform函数计算各个词语出现的次数
count = vectorizer.fit_transform(dic_data)
# print(count)
from sklearn.feature_extraction.text import TfidfTransformer
transformer = TfidfTransformer() #类调用
tfidf = transformer.fit_transform(count) #将词频统计成TF-IDF值
#查看数据结构 tfidf[i][j]表示i类文本中的tf-idf权重
print(tfidf.toarray())

2.3 Word2Vec向量法

"""
# 环境配置：pip install gensim
使用gensim进行Word2Vec进行向量化的数据格式为：
[['中华', '女子', '学院', '本科', '层次', '仅', '1', '专业', '招', '男生'], ['两天', '价', '网站', '背后', '重重', '迷雾', '做个', '网站', '究竟', '钱'], ['东', '5', '环', '海棠', '公社', '230', '290', '平', '2', '居', '准现房', '98', '折', '优惠']]
"""
from gensim.models import Word2Vec
from sklearn.decomposition import PCA
import matplotlib.pyplot as plt

stopwords = open('./data/哈工大停用词表.txt').read().split("\n")

dic = []
dic_data = []
with open('./练习data/data.txt','r',encoding='utf-8') as f:
    lines = f.read().split('\n')
    for line in lines:
        words = jieba.lcut(line)
        # for w in words:
        #     if w not in stopwords:
        #         dic.append(w)
        dic.append([w for w in words if w not in stopwords])
        dic_datas = " ".join(words)
        dic_data.append(dic_datas)
#x训练模型
model = Word2Vec(dic, vector_size=5,min_count=1,epochs=7)
#保存模型
model.save('./model.bin')
# load model
new_model = Word2Vec.load('model.bin')
print(model.wv['学院'])
print("和学院相关性最高的前5个词：",model.wv.most_similar('学院',topn=5))

## 判断词之间的相似度
print(model.wv.similarity('本科','本科'))  #1.0
## 判断词之间的相似度
print(model.wv.similarity('男生','女子'))  #-0.15

#PCA降维为2维空间
rawWordVec =[]
word2ind = {}
for i,w in enumerate(model.wv.index_to_key): #序号、词语
    word2ind[w] = i
    rawWordVec.append(model.wv[w])
rawWordVec = np.array(rawWordVec)
X_reduced  = PCA(n_components=2).fit_transform(rawWordVec)

print(X_reduced)



#绘制星空表
# 绘制星空图
# 绘制所有单词向量的二维空间投影
fig = plt.figure(figsize = (5, 5))
ax = fig.gca()
ax.set_facecolor('white')
ax.plot(X_reduced[:, 0], X_reduced[:, 1], '.', markersize = 5, alpha = 0.3, color = 'black') #黑色表示所有的词语

# 绘制几个特殊单词的向量
words = ['学院','女子']

# 设置中文字体 否则乱码 
import matplotlib
zhfont1 = matplotlib.font_manager.FontProperties(fname='./华文仿宋.ttf', size=16)
for w in words:
    if w in word2ind:
        ind = word2ind[w]
        xy = X_reduced[ind]
        plt.plot(xy[0], xy[1], '.', alpha =1, color = 'orange',markersize=10)
        plt.text(xy[0], xy[1], w, fontproperties = zhfont1, alpha = 1, color = 'red')

2.4 BERT向量法

"""
# 环境配置
1.python -V
2.conda create -n pytorch python==3.7
3.conda activate pytorch
4.打开pytorch官网：https://pytorch.org/
5.验证：
    import torch
    torch.__version__
    torch.cuda.is_available()
6.pip install transformers

使用transformers进行向量化的数据格式为：['北京欢迎你','智能科学与技术']

"""

dic = []
with open('./练习data/data.txt','r',encoding='utf-8') as f:
    lines = f.read().split('\n')
    for line in lines:
        dic.append(line)

from transformers import BertTokenizer,BertModel
from transformers import logging

logging.set_verbosity_error()

model = BertModel.from_pretrained('./bert_base_chinese')

batch_token1 = tokenizer(dic,padding=True,return_tensors='pt') #padding=True：根据最长的句子进行填充；return_tensors='pt'：表示使用pytorch版本

encoded = model(batch_token1['input_ids']) #有id转向量化过程
# print(encoded) #last_hidden_state：词向量；pooler_output：分类的输出结果
encoded_text = encoded[0] #仅仅获得词向量
print(encoded_text.shape) #torch.Size([2, 9, 768]) 2个句子*9个词id*768