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python – AttributeError:’numpy.ndarray’对象没有属性’toa

发布时间:2020-12-20 13:38:38 所属栏目:Python 来源:网络整理
导读:我正在从文本语料库中提取特征,我正在使用td-fidf矢量化器并从scikit-learn中截断奇异值分解以实现这一点.但是,由于我想要尝试的算法需要密集矩阵并且向量化器返回稀疏矩阵,我需要将这些矩阵转换为密集数组.但是,每当我尝试转换这些数组时,我都会收到错误,告
我正在从文本语料库中提取特征,我正在使用td-fidf矢量化器并从scikit-learn中截断奇异值分解以实现这一点.但是,由于我想要尝试的算法需要密集矩阵并且向量化器返回稀疏矩阵,我需要将这些矩阵转换为密集数组.但是,每当我尝试转换这些数组时,我都会收到错误,告诉我我的numpy数组对象没有属性“toarray”.我究竟做错了什么?

功能:

def feature_extraction(train,train_test,test_set):
    vectorizer = TfidfVectorizer(min_df = 3,strip_accents = "unicode",analyzer = "word",token_pattern = r'w{1,}',ngram_range = (1,2))        

    print("fitting Vectorizer")
    vectorizer.fit(train)

    print("transforming text")
    train = vectorizer.transform(train)
    train_test = vectorizer.transform(train_test)
    test_set = vectorizer.transform(test_set)

    print("Dimensionality reduction")
    svd = TruncatedSVD(n_components = 100)
    svd.fit(train)
    train = svd.transform(train)
    train_test = svd.transform(train_test)
    test_set = svd.transform(test_set)

    print("convert to dense array")
    train = train.toarray()
    test_set = test_set.toarray()
    train_test = train_test.toarray()

    print(train.shape)
    return train,test_set

追溯:

Traceback (most recent call last):
  File "C:UsersAnonymousworkspacefinal_submissionsrclinearSVM.py",line 24,in <module>
    x_train,x_test,test_set = feature_extraction(x_train,test_set)
  File "C:UsersAnonymousworkspacefinal_submissionsrcPreprocessing.py",line 57,in feature_extraction
    train = train.toarray()
AttributeError: 'numpy.ndarray' object has no attribute 'toarray'

更新:
威利指出,我对矩阵稀疏的假设可能是错误的.所以我尝试将我的数据提供给我的算法,降低维数,它实际上没有任何转换,但是当我排除维数减少时,这给了我大约53k的功能,我得到以下错误:

Traceback (most recent call last):
  File "C:UsersAnonymousworkspacefinal_submissionsrclinearSVM.py",line 28,in <module>
    result = bayesian_ridge(x_train,y_train,y_test,test_set)
  File "C:UsersAnonymousworkspacefinal_submissionsrcAlgorithms.py",line 84,in bayesian_ridge
    algo = algo.fit(x_train,y_train[:,i])
  File "C:Python27libsite-packagessklearnlinear_modelbayes.py",line 136,in fit
    dtype=np.float)
  File "C:Python27libsite-packagessklearnutilsvalidation.py",line 220,in check_arrays
    raise TypeError('A sparse matrix was passed,but dense '
TypeError: A sparse matrix was passed,but dense data is required. Use X.toarray() to convert to a dense numpy array.

有人可以解释一下吗?

UPDATE2

根据要求,我将提供所涉及的所有代码.由于它分散在不同的文件上,我只是将其分步发布.为清楚起见,我将保留所有模块导入.

这是我预处理代码的方式:

def regexp(data):
    for row in range(len(data)):
        data[row] = re.sub(r'[W_]+'," ",data[row])
        return data

def clean_the_text(data):
    alist = []
    data = nltk.word_tokenize(data)
    for j in data:
        j = j.lower()
        alist.append(j.rstrip('n'))
    alist = " ".join(alist)
    return alist
def loop_data(data):
    for i in range(len(data)):
        data[i] = clean_the_text(data[i])
    return data  


if __name__ == "__main__":
    print("loading train")
    train_text = porter_stemmer(loop_data(regexp(list(np.array(p.read_csv(os.path.join(dir,"train.csv")))[:,1]))))
    print("loading test_set")
    test_set = porter_stemmer(loop_data(regexp(list(np.array(p.read_csv(os.path.join(dir,"test.csv")))[:,1]))))

在将train_set拆分为x_train和x_test进行交叉验证后,我使用上面的feature_extraction函数转换数据.

x_train,test_set)

最后,我将它们输入我的算法

def bayesian_ridge(x_train,test_set):
    algo = linear_model.BayesianRidge()
    algo = algo.fit(x_train,y_train)
    pred = algo.predict(x_test)
    error = pred - y_test
    result.append(algo.predict(test_set))
    print("Bayes_error: ",cross_val(error))
    return result

解决方法

TruncatedSVD.transform返回一个数组,而不是稀疏矩阵.事实上,在scikit-learn的当前版本中,只有矢量化器返回稀疏矩阵.

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