Sci-Kit学习:将朴素贝叶斯模型预测纳入Logistic回归?

时间:2017-12-18 17:05:34

标签: python-3.x machine-learning scikit-learn nlp logistic-regression

我有各种客户属性的数据(自我描述和年龄),以及这些客户是否会购买特定产品的二元结果

  {"would_buy": "No", 
  "self_description": "I'm a college student studying biology", 
  "Age": 19}, 

我想在self-description上使用MultinomialNB来预测would_buy,然后将这些预测合并到would_buy上的逻辑回归模型中将age作为协变量。

目前为止的文本模型代码(我是SciKit的新手!),带有简化的数据集。

from sklearn.naive_bayes import MultinomialNB
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.model_selection import train_test_split
from sklearn.metrics import classification_report

#Customer data that includes whether a customer would buy an item (what I'm interested), their self-description, and their age. 
data = [
  {"would_buy": "No", "self_description": "I'm a college student studying biology", "Age": 19}, 
  {"would_buy": "Yes", "self_description": "I'm a blue-collar worker", "Age": 20},
  {"would_buy": "No", "self_description": "I'm a Stack Overflow denzien", "Age": 56}, 
  {"would_buy": "No", "self_description": "I'm a college student studying economics", "Age": 20}, 
  {"would_buy": "Yes", "self_description": "I'm a UPS worker", "Age": 35}, 
  {"would_buy": "No", "self_description": "I'm a Stack Overflow denzien", "Age": 56}
  ]

def naive_bayes_model(customer_data):
  self_descriptions = [customer['self_description'] for customer in customer_data]
  decisions = [customer['would_buy'] for customer in customer_data]

  vectorizer = TfidfVectorizer(stop_words='english', ngram_range=(1,2))
  X = vectorizer.fit_transform(self_descriptions, decisions)
  naive_bayes = MultinomialNB(alpha=0.01)
  naive_bayes.fit(X, decisions)
  train(naive_bayes, X, decisions)

def train(classifier, X, y):
    X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.25, random_state=22)
    classifier.fit(X_train, y_train)

    print(classification_report(classifier.predict(X_test), y_test))


def main():
  naive_bayes_model(data)



main()

1 个答案:

答案 0 :(得分:1)

简短的回答是使用受过训练的naive_bayes上的predict_probapredict_log_proba方法为逻辑回归模型创建输入。这些可以与Age值连接,以便为LogisticRegression模型创建训练和测试集。

但是,我想指出您编写的代码在培训后无法访问您的naive_bayes模型。因此,您肯定需要重新构建代码。

除了这个问题之外,这就是我将naive_bayes的输出合并到LogisticRegression的方法:

descriptions = np.array([customer['self_description'] for customer in data])
decisions = np.array([customer['would_buy'] for customer in data])
ages = np.array([customer['Age'] for customer in data])

vectorizer = TfidfVectorizer(stop_words='english', ngram_range=(1,2))
desc_vec = vectorizer.fit_transform(descriptions, decisions)
naive_bayes = MultinomialNB(alpha=0.01)
desc_train, desc_test, age_train, age_test, dec_train, dec_test = train_test_split(desc_vec, ages, decisions, test_size=0.25, random_state=22)

naive_bayes.fit(desc_train, dec_train)
nb_train_preds = naive_bayes.predict_proba(desc_train)
lr = LogisticRegression()
lr_X_train = np.hstack((nb_tarin_preds, age_train.reshape(-1, 1)))
lr.fit(lr_X_train, dec_train)

lr_X_test = np.hstack((naive_bayes.predict_proba(desc_test), age_test.reshape(-1, 1)))
lr.score(lr_X_test, dec_test)