utils.py 文件源码

def build_feature_matrix(documents, feature_type='frequency'):

    feature_type = feature_type.lower().strip()  

    if feature_type == 'binary':
        vectorizer = CountVectorizer(binary=True, min_df=1, 
                                     ngram_range=(1, 1))
    elif feature_type == 'frequency':
        vectorizer = CountVectorizer(binary=False, min_df=1, 
                                     ngram_range=(1, 1))
    elif feature_type == 'tfidf':
        vectorizer = TfidfVectorizer(min_df=1, 
                                     ngram_range=(1, 1))
    else:
        raise Exception("Wrong feature type entered. Possible values: 'binary', 'frequency', 'tfidf'")

    feature_matrix = vectorizer.fit_transform(documents).astype(float)

    return vectorizer, feature_matrix