word2sequence 把字符串转换数字编码

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。

1.准备数据

dataset.py

'''
准备数据
'''
from torch.utils.data import DataLoader,Dataset
import torch
import utils
import os
import config

class ImdbDataset(Dataset):
    def __init__(self,train = True):
        data_path = r"H:\073-nlp自然语言处理-v5.bt38[周大伟]\073-nlp自然语言处理-v5.bt38[周大伟]\第四天\代码\data\aclImdb_v1\aclImdb"
        super(ImdbDataset,self).__init__()
        data_path += r"\train" if train else r"\test"
        self.total_path = []
        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]
        review = utils.tokenlize(open(file,encoding='utf-8').read())
        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 collate_fn(batch):
# 	#batch是list，其中是一个一个元组，每个元组是dataset中__getitem__的结果
#     batch = list(zip(*batch))
#     labes = torch.tensor(batch[1],dtype=torch.int32)
#     texts = batch[0]
#     del batch
#     return labes,texts

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([config.ws.transform(i,max_len=config.max_len) for i in reviews])
    labels = torch.LongTensor(labels)

    return reviews,labels

def get_dataloader(train=True):
    dataset = ImdbDataset(train)
    batch_size = config.train_batch_size if train else config.test_batch_size
    return DataLoader(dataset,batch_size=batch_size,shuffle=True,collate_fn=collate_fn)

if __name__ == '__main__':
    dataset = ImdbDataset()
    dataloader = DataLoader(dataset=dataset, batch_size=2, shuffle=True,collate_fn=collate_fn)
    # 3. 观察数据输出结果
    for idx, (label, text) in enumerate(dataloader):
        print("idx：", idx)
        print("table:", label)
        print("text:", text)
        break

　　

2.conf.py 文件

"""
配置文件
"""
import pickle

train_batch_size = 512
test_batch_size = 500

ws = pickle.load(open("./model/ws.pkl","rb"))

max_len = 80

　　

3.utils.py分词文件

import re

def tokenlize(sentence):
    '''
    进行文本分词
    :param sentence:
    :return:
    '''

    fileters = ['!', '"', '#', '$', '%', '&', '\(', '\)', '\*', '\+', ',', '-', '\.', '/', ':', ';', '<', '=', '>',
                '\?', '@'
        , '\[', '\\', '\]', '^', '_', '`', '\{', '\|', '\}', '~', '\t', '\n', '\x97', '\x96', '”', '“', ]
    sentence = sentence.lower()
    sentence = re.sub("<br />"," ",sentence)
    sentence = re.sub("|".join(fileters)," ",sentence)
    # result = sentence.split(" ")
    #去除空字符串
    result = [i for i in sentence.split(" ") if len(i)>0]
    return result

　　

4.word2sequence.py   句子中的词转换成数字编码

'''
文本序列化
'''
class Word2Sequence:
    UNK_TAG = "<UNK>"
    PAD_TAG = "<PAD>"
    UNK = 0
    PAD = 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:
        :return:
        '''
        for word in sentence:
            self.count[word] = self.count.get(word,0) + 1

    def build_vocab(self,min_count = 1,max_count = None,max_feature = 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_feature: 最大词语数,这个参数会排序
        :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_feature is not None:
            self.count = dict(sorted(self.count.items(),lambda x:x[-1],reverse=True)[:max_feature])

        for word in self.count.keys():
            self.dict[word] = len(self.dict)  #获取每个词及生成每个词对应的编号

        #字典翻转，键→值，值←键
        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 sentense: [str,str,,,,,,,,,,]
        :return: [num,num,num,,,,,,,]
        '''
        if len(sentence) > max_len:
            sentence = sentence[:max_len]
        else:
            sentence = sentence + [self.PAD_TAG]*(max_len-len(sentence))
        return [self.dict.get(i,0) for i in sentence]

    def inverse_transform(self,incides):
        '''
        把数字序列转化为字符
        :param incides: [num,num,num,,,,,,,,]
        :return: [str,str,str,,,,,,,]
        '''
        return [self.inverse_dict.get(i,"<UNK>") for i in incides]

if __name__ == '__main__':

    sentences = [['今天','天气','很','好'],
                ['今天','去','吃','什么']]

    ws = Word2Sequence()
    for sentence in sentences:
        ws.fit(sentence)
    ws.build_vocab()
    print(ws.dict)
    ret = ws.transform(["好","好","好","好","好","好","好","热","呀"],max_len=20)
    print(ret)
    ret = ws.inverse_transform(ret)
    print(ret)

　　

5. main主文件，把文件中的词转换成数字编码并保存

'''
文本序列化及保存模型
'''

from word_sequence import Word2Sequence
from dataset import get_dataloader
import pickle
from tqdm import tqdm

if __name__ == '__main__':
    ws = Word2Sequence()
    dl_train = get_dataloader(True)
    dl_test = get_dataloader(False)
    for label,reviews in tqdm(dl_train,total=len(dl_train)):
        for review in reviews:
            ws.fit(review)
    for label,reviews in tqdm(dl_test,total=len(dl_train)):
        for review in reviews:
            ws.fit(review)
    ws.build_vocab()

    pickle.dump(ws,open("./model/ws.pkl","wb"))