11.29
1. 数据准备:收集数据与读取
2. 数据预处理:处理数据
3. 训练集与测试集:将先验数据按一定比例进行拆分。
4. 提取数据特征,将文本解析为词向量 。
5. 训练模型:建立模型,用训练数据训练模型。即根据训练样本集,计算词项出现的概率P(xi|y),后得到各类下词汇出现概率的向量 。
6. 测试模型:用测试数据集评估模型预测的正确率。
混淆矩阵
准确率、精确率、召回率、F值
#将其向量化 from sklearn.feature_extraction.text import TfidfVectorizer vectorizer=TfidfVectorizer(min_df=2,ngram_range=(1,2),stop_words='english',strip_accents='unicode',norm='l2') X_train=vectorizer.fit_transform(x_train) X_test=vectorizer.transform(x_test) #预处理 def preprocessing(text): #text=text.decode("utf-8") tokens=[word for sent in nltk.sent_tokenize(text) for word in nltk.word_tokenize(sent)] stops=stopwords.words('english') tokens=[token for token in tokens if token not in stops] tokens=[token.lower() for token in tokens if len(token)>=3] lmtzr=WordNetLemmatizer() tokens=[lmtzr.lemmatize(token) for token in tokens] preprocessed_text=' '.join(tokens) return preprocessed_text import nltk for sent in nltk.sent_tokenize(text): for token in nltk.word_tokenize(sent): print(token)
#将其向量化 from sklearn.model_selection import train_test_split x_train,x_test,y_train,y_test = train_test_split(sms_data,sms_label,test_size=0.3,random_state=0,stratify=sms_label) from sklearn.feature_extraction.text import TfidfVectorizer vectorizer=TfidfVectorizer(min_df=2,ngram_range=(1,2),stop_words='english',strip_accents='unicode',norm='12') X_train=vectorizer.fit_transform(x_train) X_test=vectorizer.transform(x_test) #朴素贝叶斯 from sklearn.naive_bayes import MultinomialNB clf=MultinomialNB().fit(x_train,y_train) #测试模型 from sklearn.metrics import confusion_matrix from sklearn.metrics import classification_report cm=confusion_matrix(y_test.y_nb_pred) print(cm) cr=classification_report(y_test.y_nb_pred) print(cr)
https://scikit-learn.org/stable/modules/generated/sklearn.feature_extraction.text.TfidfVectorizer.html