英文电影评论情感分析
分析步骤
数据集
现在我们有一个经典的数据集IMDB数据集，地址：http://ai.stanford.edu/~amaas/data/sentiment/，这是一份包含了5万条流行电影的评论数据，其中训练集25000条，测试集25000条。数据格式如下：
下图左边为名称，其中名称包含两部分，分别是序号和情感评分，（1-4为neg，5-10为pos），右边为评论内容。
文本预处理
文本是一类序列数据，一篇文章可以看作是字符或单词的序列，本节将介绍文本数据的常见预处理步骤，预处理通常包括四个步骤：
-
读入文本
-
分词
-
建立字典，将每个词映射到一个唯一的索引（index）
-
将文本从词的序列转换为索引的序列，方便输入模型
文本的tokenization
tokenization就是通常所说的分词，分出的每一个词语我们把它称为token。
常见的分词工具很多，比如：
-
jieba分词：https://github.com/fxsjy/jieba -
清华大学的分词工具THULAC：
https://github.com/thunlp/THULAC-Python
构造词典
这里我们可以考虑把文本中的每个词语和其对应的数字，使用字典保存，同时实现方法把句子通过字典映射为包含数字的列表。
实现文本序列化之前，考虑以下几点:
-
如何使用字典把词语和数字进行对应
-
不同的词语出现的次数不尽相同，是否需要对高频或者低频词语进行过滤，以及总的词语数量是否需要进行限制
-
得到词典之后，如何把句子转化为数字序列，如何把数字序列转化为句子
-
不同句子长度不相同，每个batch的句子如何构造成相同的长度（可以对短句子进行填充，填充特殊字符）
-
对于新出现的词语在词典中没有出现怎么办（可以使用特殊字符代理）
思路分析：
-
对所有句子进行分词
-
词语存入字典，根据次数对词语进行过滤，并统计次数
-
实现文本转数字序列的方法
-
实现数字序列转文本方法
# -*-coding:utf-8-*-
import pickle
from tqdm import tqdm
from 情感分析.imdb_sentiment import dataset
# from 情感分析.imdb_sentiment.vocab import Vocab
from torch.utils.data import DataLoader
class Vocab:
UNK_TAG = "<UNK>" # 表示未知字符
PAD_TAG = "<PAD>" # 填充符
PAD = 0
UNK = 1
def __init__(self):
self.dict = { # 保存词语和对应的数字
self.UNK_TAG: self.UNK,
self.PAD_TAG: self.PAD
}
self.count = {} # 统计词频的
def fit(self, sentence):
"""
接受句子，统计词频
:param sentence:[str,str,str]
:return:None
"""
for word in sentence:
self.count[word] = self.count.get(word, 0) + 1 # 所有的句子fit之后，self.count就有了所有词语的词频
def build_vocab(self, min_count=1, max_count=None, max_features=None):
"""
根据条件构造 词典
:param min_count:最小词频
:param max_count: 最大词频
:param max_features: 最大词语数
:return:
"""
if min_count is not None:
self.count = {word: count for word, count in self.count.items() if count >= min_count}
if max_count is not None:
self.count = {word: count for word, count in self.count.items() if count <= max_count}
if max_features is not None:
# [(k,v),(k,v)....] --->{k:v,k:v}
self.count = dict(sorted(self.count.items(), lambda x: x[-1], reverse=True)[:max_features])
for word in self.count:
self.dict[word] = len(self.dict) # 每次word对应一个数字
# 把dict进行翻转
self.inverse_dict = dict(zip(self.dict.values(), self.dict.keys()))
def transform(self, sentence, max_len=None):
"""
把句子转化为数字序列
:param sentence:[str,str,str]
:return: [int,int,int]
"""
if len(sentence) > max_len:
sentence = sentence[:max_len]
else:
sentence = sentence + [self.PAD_TAG] * (max_len - len(sentence)) # 填充PAD
return [self.dict.get(i, 1) for i in sentence]
def inverse_transform(self, incides):
"""
把数字序列转化为字符
:param incides: [int,int,int]
:return: [str,str,str]
"""
return [self.inverse_dict.get(i, "<UNK>") for i in incides]
def __len__(self):
return len(self.dict)
def collate_fn(batch):
"""
对batch数据进行处理
:param batch: [一个getitem的结果，getitem的结果,getitem的结果]
:return: 元组
"""
reviews, labels = zip(*batch)
return reviews, labels
def get_dataloader(train=True):
imdb_dataset = dataset.ImdbDataset(train)
my_dataloader = DataLoader(imdb_dataset, batch_size=200, shuffle=True, collate_fn=collate_fn)
return my_dataloader
if __name__ == '__main__':
# sentences = [["今天", "天气", "很", "好"],
# ["今天", "去", "吃", "什么"]]
# ws = Vocab()
# for sentence in sentences:
# # 统计词频
# ws.fit(sentence)
# # 构造词典
# ws.build_vocab(min_count=1)
# print(ws.dict)
# # 把句子转换成数字序列
# ret = ws.transform(["好", "好", "好", "好", "好", "好", "好", "热", "呀"], max_len=13)
# print(ret)
# # 把数字序列转换成句子
# ret = ws.inverse_transform(ret)
# print(ret)
# pass
ws = Vocab()
dl_train = get_dataloader(True)
dl_test = get_dataloader(False)
for reviews, label in tqdm(dl_train, total=len(dl_train)):
for sentence in reviews:
ws.fit(sentence)
for reviews, label in tqdm(dl_test, total=len(dl_test)):
for sentence in reviews:
ws.fit(sentence)
ws.build_vocab()
print(len(ws))
pickle.dump(ws, open("./models/vocab.pkl", "wb"))
会生成对应的词典pkl文件
构造Dataset与Dataloader
# -*-coding:utf-8-*-
import os
import pickle
import re
import zipfile
from torch.utils.data import Dataset, DataLoader
from tqdm import tqdm
class ImdbDataset(Dataset):
def __init__(self, train=True):
# super(ImdbDataset,self).__init__()
if not os.path.exists("./data/download"):
unzip_file("./data/test.zip", "./data/download")
unzip_file("./data/train.zip", "./data/download")
data_path = r"./data/download"
data_path += r"/train" if train else r"/test"
self.total_path = [] # 保存所有的文件路径
for temp_path in [r"/pos", r"/neg"]:
cur_path = data_path + temp_path
self.total_path += [os.path.join(cur_path, i) for i in os.listdir(cur_path) if i.endswith(".txt")]
def __getitem__(self, idx):
file = self.total_path[idx]
# 从txt获取评论并分词
review = tokenlize(open(file, "r", encoding="utf-8").read())
# 获取评论对应的label
label = int(file.split("_")[-1].split(".")[0])
label = 0 if label < 5 else 1
return review, label
def __len__(self):
return len(self.total_path)
def tokenlize(sentence):
"""
进行文本分词
:param sentence: str
:return: [str,str,str]
"""
fileters = ['!', '"', '#', '$', '%', '&', '\(', '\)', '\*', '\+', ',', '-', '\.', '/', ':', ';', '<', '=', '>',
'\?', '@', '\[', '\\', '\]', '^', '_', '`', '\{', '\|', '\}', '~', '\t', '\n', '\x97', '\x96', '”',
'“', ]
sentence = sentence.lower() # 把大写转化为小写
sentence = re.sub("<br />", " ", sentence)
# sentence = re.sub("I'm","I am",sentence)
# sentence = re.sub("isn't","is not",sentence)
sentence = re.sub("|".join(fileters), " ", sentence)
result = [i for i in sentence.split(" ") if len(i) > 0]
return result
def unzip_file(zip_src, dst_dir):
"""
解压缩
:param zip_src:
:param dst_dir:
:return:
"""
r = zipfile.is_zipfile(zip_src)
if r:
fz = zipfile.ZipFile(zip_src, 'r')
bar = tqdm(fz.namelist())
bar.set_description("unzip " + zip_src)
for file in bar:
fz.extract(file, dst_dir)
else:
print('This is not zip')
# 以下为调试代码
def collate_fn(batch):
"""
对batch数据进行处理
:param batch: [一个getitem的结果，getitem的结果,getitem的结果]
:return: 元组
"""
reviews, labels = zip(*batch)
return reviews, labels
# def test_file(train=True):
# if not os.path.exists("./data/download"):
# unzip_file("./data/data.zip", "./data/download")
# data_path = r"./data/download"
# data_path += r"/train" if train else r"/test"
# total_path = [] # 保存所有的文件路径
# for temp_path in [r"/pos", r"/neg"]:
# cur_path = data_path + temp_path
# total_path += [os.path.join(cur_path, i) for i in os.listdir(cur_path) if i.endswith(".txt")]
# print(total_path)
if __name__ == "__main__":
from 情感分析.imdb_sentiment.vocab import Vocab
imdb_dataset = ImdbDataset(True)
my_dataloader = DataLoader(imdb_dataset, batch_size=2, shuffle=True, collate_fn=collate_fn)
for review,label in my_dataloader:
vocab_model = pickle.load(open("./models/vocab.pkl", "rb"))
print(review[0])
result = vocab_model.transform(review[0], 100)
print(result)
break
# unzip_file("./data/a.zip", "./data/download")
# if os.path.exists("./data/download"):
# print("T")
# data = open("./data/download/train/pos\\10032_10.txt", "r", encoding="utf-8").read()
# result = tokenlize("--or something like that. Who the hell said that theatre stopped at the orchestra pit--or even at the theatre door?")
# result = tokenlize(data)
# print(result)
# test_file()
测试输出：
['this', 'movie', 'was', 'kind', 'of', 'interesting', 'i', 'had', 'to', 'watch', 'it', 'for', 'a', 'college', 'class', 'about', 'india', 'however', 'the', 'synopsis', 'tells', 'you', 'this', 'movie', 'is', 'about', 'one', 'thing', 'when', 'it', "doesn't", 'really', 'contain', 'much', 'cold', 'hard', 'information', 'on', 'those', 'details', 'it', 'is', 'not', 'really', 'true', 'to', 'the', 'synopsis', 'until', 'the', 'very', 'end', 'where', 'they', 'sloppily', 'try', 'to', 'tie', 'all', 'the', 'elements', 'together', 'the', 'gore', 'factor', 'is', 'superb', 'however', 'even', 'right', 'at', 'the', 'very', 'beginning', 'you', 'want', 'to', 'look', 'away', 'because', 'the', 'gore', 'is', 'pretty', 'intense', 'only', 'watch', 'this', 'movie', 'if', 'you', 'want', 'to', 'see', 'some', 'cool', 'gore', 'because', 'the', 'plot', 'is', 'thin', 'and', 'will', 'make', 'you', 'sad', 'that', 'you', 'wasted', 'time', 'listening', 'to', 'it', "i've", 'seen', 'rumors', 'on', 'other', 'websites', 'about', 'this', 'movie', 'being', 'based', 'on', 'true', 'events', 'however', 'you', 'can', 'not', 'find', 'any', 'information', 'about', 'it', 'online', 'so', 'basically', 'this', 'movie', 'was', 'a', 'waste', 'of', 'time', 'to', 'watch']
[2, 3, 93, 390, 14, 181, 90, 136, 100, 312, 7, 17, 78, 5879, 1056, 80, 17356, 117, 18, 6179, 3176, 12, 2, 3, 4, 80, 16, 187, 128, 7, 642, 483, 1011, 314, 987, 1655, 2011, 122, 48, 1176, 7, 4, 8, 483, 496, 100, 18, 6179, 1636, 18, 52, 458, 429, 329, 46669, 2039, 100, 11337, 36, 18, 1366, 753, 18, 2188, 10851, 4, 14736, 117, 9, 855, 58, 18, 52, 2691, 12, 116, 100, 266, 1061, 223, 18, 2188, 4, 819, 371, 308, 312, 2, 3, 11, 12, 116, 100, 46, 65, 710, 2188, 223, 18, 106]
word embedding
word embedding是深度学习中表示文本常用的一种方法。和one-hot编码不同，word embedding使用了浮点型的稠密矩阵来表示token。根据词典的大小，我们的向量通常使用不同的维度，例如100,256,300等。其中向量中的每一个值是一个参数，其初始值是随机生成的，之后会在训练的过程中进行学习而获得。
如果我们文本中有20000个词语，如果使用one-hot编码，那么我们会有20000*20000的矩阵，其中大多数的位置都为0，但是如果我们使用word embedding来表示的话，只需要20000* 维度，比如20000*300
我们会把所有的文本转化为向量，把句子用向量来表示
但是在这中间，我们会先把token使用数字来表示，再把数字使用向量来表示。
即：token---> num ---->vector
word embedding API
torch.nn.Embedding(num_embeddings,embedding_dim)
参数介绍：
-
num_embeddings：词典的大小 -
embedding_dim：embedding的维度
使用方法：
embedding = nn.Embedding(vocab_size,300) #实例化
input_embeded = embedding(input) #进行embedding的操作
embedding模型
# -*-coding:utf-8-*-
import pickle
import torch
import torch.nn as nn
import torch.nn.functional as F
from torch.optim import Adam
from torch.utils.data import DataLoader
from tqdm import tqdm
from 情感分析.imdb_sentiment import dataset
from 情感分析.imdb_sentiment.vocab import Vocab
train_batch_size = 512
test_batch_size = 500
voc_model = pickle.load(open("./models/vocab.pkl", "rb"))
sequence_max_len = 20
def collate_fn(batch):
"""
对batch数据进行处理
:param batch: [一个getitem的结果，getitem的结果,getitem的结果]
:return: 元组
"""
reviews, labels = zip(*batch)
reviews = torch.LongTensor([voc_model.transform(i, max_len=sequence_max_len) for i in reviews])
labels = torch.LongTensor(labels)
return reviews, labels
def get_dataloader(train=True):
imdb_dataset = dataset.ImdbDataset(train)
batch_size = train_batch_size if train else test_batch_size
return DataLoader(imdb_dataset, batch_size=batch_size, shuffle=True, collate_fn=collate_fn)
class ImdbModel(nn.Module):
def __init__(self):
super(ImdbModel, self).__init__()
self.embedding = nn.Embedding(num_embeddings=len(voc_model), embedding_dim=200,
padding_idx=voc_model.PAD)
self.fc = nn.Linear(sequence_max_len * 200, 2)
def forward(self, input):
"""
:param input:[batch_size,max_len]
:return:
"""
input_embeded = self.embedding(input) # input embeded :[batch_size,max_len,200]
# 变形
input_embeded_viewed = input_embeded.view(input_embeded.size(0), -1)
# 全连接
out = self.fc(input_embeded_viewed)
return F.log_softmax(out, dim=-1)
def device():
if torch.cuda.is_available():
return torch.device('cuda')
else:
return torch.device('cpu')
def train(imdb_model, epoch):
"""
:param imdb_model:
:param epoch:
:return:
"""
train_dataloader = get_dataloader(train=True)
# bar = tqdm(train_dataloader, total=len(train_dataloader))
optimizer = Adam(imdb_model.parameters())
for i in range(epoch):
bar = tqdm(train_dataloader, total=len(train_dataloader))
for idx, (data, target) in enumerate(bar):
optimizer.zero_grad()
data = data.to(device())
target = target.to(device())
output = imdb_model(data)
loss = F.nll_loss(output, target)
loss.backward()
optimizer.step()
bar.set_description("epcoh:{} idx:{} loss:{:.6f}".format(i, idx, loss.item()))
torch.save(imdb_model,'fc_model.pkl')
def test(imdb_model):
"""
验证模型
:param imdb_model:
:return:
"""
test_loss = 0
correct = 0
imdb_model.eval()
test_dataloader = get_dataloader(train=False)
with torch.no_grad():
for data, target in tqdm(test_dataloader):
data = data.to(device())
target = target.to(device())
output = imdb_model(data)
test_loss += F.nll_loss(output, target, reduction='sum').item()
pred = output.data.max(1, keepdim=True)[1] # 获取最大值的位置,[batch_size,1]
correct += pred.eq(target.data.view_as(pred)).sum()
test_loss /= len(test_dataloader.dataset)
print('\nTest set: Avg. loss: {:.4f}, Accuracy: {}/{} ({:.2f}%)\n'.format(
test_loss, correct, len(test_dataloader.dataset),
100. * correct / len(test_dataloader.dataset)))
#单句测试
def xlftest():
import numpy as np
model=torch.load('fc_model.pkl')
model.to(device())
from 情感分析.imdb_sentiment.xlftest import tokenlize
line = open('./data/download/test/neg\\1_3.txt', "r", encoding="utf-8").read()
print(line)
review = tokenlize(open('./data/download/test/neg\\1_3.txt', "r", encoding="utf-8").read())
vocab_model = pickle.load(open("./models/vocab.pkl", "rb"))
result = vocab_model.transform(review, 20)
# print(result)
target=0
target=torch.LongTensor(target).to(device())
data=torch.LongTensor(result).to(device())
data=torch.reshape(data,(1,20))
print(data.shape)
output = model(data)
pred = output.data.max(1, keepdim=True)[1] # 获取最大值的位置,[batch_size,1]
#print(pred.item())
if pred.item()==0:
print("消极")
else:
print("积极")
if __name__ == '__main__':
imdb_model = ImdbModel().to(device())
train(imdb_model, 4)
test(imdb_model)
xlftest()
会生成对应的模型保存文件
导入可对其进行单独测试
准确率60%
基于LSTM情感分析
超参数
train_batch_size = 512
test_batch_size = 128
sequence_max_len = 100
模型
class ImdbModel(nn.Module):
def __init__(self):
super(ImdbModel, self).__init__()
self.embedding = nn.Embedding(num_embeddings=len(voc_model), embedding_dim=200, padding_idx=voc_model.PAD).to()
self.lstm = nn.LSTM(input_size=200, hidden_size=64, num_layers=2, batch_first=True, bidirectional=True,
dropout=0.5)
self.fc1 = nn.Linear(64 * 2, 64)
self.fc2 = nn.Linear(64, 2)
def forward(self, input):
"""
:param input:[batch_size,max_len]
:return:
"""
input_embeded = self.embedding(input) # input embeded :[batch_size,max_len,200]
output, (h_n, c_n) = self.lstm(input_embeded) # h_n :[4,batch_size,hidden_size]
# out :[batch_size,hidden_size*2]
out = torch.cat([h_n[-1, :, :], h_n[-2, :, :]], dim=-1) # 拼接正向最后一个输出和反向最后一个输出
# 进行全连接
out_fc1 = self.fc1(out)
# 进行relu
out_fc1_relu = F.relu(out_fc1)
# 全连接
out_fc2 = self.fc2(out_fc1_relu) # out :[batch_size,2]
return F.log_softmax(out_fc2, dim=-1)
训练
def train(imdb_model, epoch):
"""
:param imdb_model:
:param epoch:
:return:
"""
train_dataloader = get_dataloader(train=True)
optimizer = Adam(imdb_model.parameters())
for i in range(epoch):
bar = tqdm(train_dataloader, total=len(train_dataloader))
for idx, (data, target) in enumerate(bar):
optimizer.zero_grad()
data = data.to(device())
target = target.to(device())
output = imdb_model(data)
loss = F.nll_loss(output, target)
loss.backward()
optimizer.step()
bar.set_description("epcoh:{} idx:{} loss:{:.6f}".format(i, idx, loss.item()))
torch.save(imdb_model, 'lstm_model.pkl')
测试
def test(imdb_model):
"""
验证模型
:param imdb_model:
:return:
"""
test_loss = 0
correct = 0
imdb_model.eval()
test_dataloader = get_dataloader(train=False)
with torch.no_grad():
for data, target in tqdm(test_dataloader):
data = data.to(device())
target = target.to(device())
output = imdb_model(data)
test_loss += F.nll_loss(output, target, reduction='sum').item()
pred = output.data.max(1, keepdim=True)[1] # 获取最大值的位置,[batch_size,1]
correct += pred.eq(target.data.view_as(pred)).sum()
test_loss /= len(test_dataloader.dataset)
print('\nTest set: Avg. loss: {:.4f}, Accuracy: {}/{} ({:.2f}%)\n'.format(
test_loss, correct, len(test_dataloader.dataset),
100. * correct / len(test_dataloader.dataset)))
单条测试
def xlftest():
import numpy as np
model = torch.load('lstm_model.pkl')
model.to(device())
from 情感分析.imdb_sentiment.xlftest import tokenlize
line=open('./data/download/test/neg\\1_3.txt', "r", encoding="utf-8").read()
print(line)
review = tokenlize(open('./data/download/test/neg\\1_3.txt', "r", encoding="utf-8").read())
# review=tokenlize(line)
vocab_model = pickle.load(open("./models/vocab.pkl", "rb"))
result = vocab_model.transform(review, 20)
# print(result)
target = 0
target = torch.LongTensor(target).to(device())
data = torch.LongTensor(result).to(device())
data = data=torch.reshape(data,(1,20))
# print(data.shape)
output = model(data)
pred = output.data.max(1, keepdim=True)[1] # 获取最大值的位置,[batch_size,1]
# print(pred.item())
if pred.item() == 0:
print("消极")
else:
print("积极")
测试效果
提升了一些
明日任务
实现中文情感分析
