朴素贝叶斯实现文本分类
文本分类
词语去重¶
import randomimport jiebaimport sklearnfrom sklearn.naive_bayes import MultinomialNBimport numpy as npimport matplotlib.pyplot as pltimport pylab as pldef set_word(filename):word_set = set()with open(filename,'r+') as f:for line in f.readlines():word = line.strip().decode('utf-8')if len(word) > 0 and word not in word_set:word_set.add(word)return word_set
文本处理
import osdef text_Processing(file_path,test_size = 0.2):file_list = os.listdir(file_path)data_list = []class_list = []for file in file_list:new_file_path = os.path.join(file_path,file)files = os.listdir(new_file_path)j = 1for file_ in files:if j>100:breakwith open(os.join(new_file_path,file_),'r+') as f:raw = f.read()#jieba并行分词(window不可用),参数为进程数word_cut = jie.cut(raw,cut_all = False) #精确模式words_list = list[word_cut]jieba.disable_parallel()#释放进程#文件夹名就是分类j += 1##划分训练集和测试集data_class_list = zip(data_list,class_list)random.shuffle(data_class_list)index = int(len(data_class_list)*test_size) + 1train_list = data_class_list[index:]test_list = data_class_listp[:index]= zip(*train_list)= zip(*test_list)#统计词频all_words_dict = {}for word_list in train_data_list:for word in word_list:if all_words_dict[word]:+= 1else:+= 1all_words_tuple_lsit = sorted(all_words_dict.items,key=lambda f:f[1],reverse=True)all_words_list = list(zip(*all_words_tuple_lsit)[0])return all_words_list,train_data_list,test_class_list,train_class_list
选取特征词
def words_dict(all_words_list,deletN,stopwords_set = set()):feature_words = []n = 1for t in range(deletN,len(all_words_list),1):if n > 1000: #特征词的维度1000breakif not all_words_list[t].isdigit() and all_words_list[t] not in stopwords_set and 1 < len(all_words_list[t]) < 5:feature_words.append(all_words_list[t])n += 1return feature_words
文本特征
def text_features(train_data_list,test_data_list,feature_words,flag='sklearn'):def rapper(text,feature_words):text_words = set(text)if flag == 'nltk':features = {word:1 if word in text_words else 0 for word in feature_words}elif flag == 'sklearn':features = [1 if word in text_words else 0 for word in feature_words]else:features = []return featurestrain_feature_list = [rapper(text,feature_words) for text in train_data_list]test_feature_list = [rapper(text_,feature_words) for text_ in test_data_list]return train_feature_list,test_feature_list
分类,同时输出准确率
import nltkdef text_classifier(train_feature_list,test_feature_list,train_class_list,test_class_list,flag = 'sklearn'):if flag == 'nltk':train_flist = zip(train_feature_list,train_class_list)test_flist = zip(test_feature_list,test_class_list)classifier = nltk.classify.NaiveBayesClassifier.train(train_flist)test_accuracy = nltk.classify.accuracy(classifier,test_flist)elif flag == 'sklearn':classifier = MultinomialNB.fit(train_feature_list,train_class_list) #多项式朴素贝叶斯fittest_accuracy = classifier.score(test_feature_list,test_class_list) # 对测试集打分else:test_accuracy = []return test_accuracy
实战
print('start')##文本预处理file_path('./testdata')all_words_list,train_data_list,test_class_list,train_class_list = text_Processing(file_path,test_size=0.2)stopwords_file = './stopwords.txt'stopwords_set = set_word(stopwords_file)## 文本特征提取和分类flag = 'sklearn'deleteNs = range(0,1000,20)test_accuracy_list = []for deleteN in deleteNs:feature_word = words_dict(all_words_list,deletN,stopwords_set)train_feature_list,test_feature_list = text_features(train_data_list,test_data_list,feature_word,flag)test_acctacy = text_classifier(train_feature_list,test_feature_list,train_class_list,test_class_list)test_accuracy_list.append(test_acctacy)print(test_accuracy_list)print(finished)
可以从搜狗语料库下载数据集
