如何在 Python 中组合文本特征和分类特征

Question

>我正在尝试构建一个管道来分别转换和编码文本和分类特征，并将它们组合到分类器中。我目前有以下类来选择数据：

class DataFrameSelector(BaseEstimator, TransformerMixin):
    def __init__(self, attribute_names):
        self.attribute_names = attribute_names
    def fit(self, X, y=None):
        return self
    def transform(self, X):
        print(X[self.attribute_names].head())
        return X[self.attribute_names]

然后使用它，我将以下功能联盟与管道结合使用：

preprocessing = FeatureUnion([
    ("text_pipeline", Pipeline([
        ("select_text", DataFrameSelector(text_features)),
        ("count_vect", CountVectorizer()),
        ("word_count_to_vector", TfidfTransformer()),
    ])),
    ("cat_pipeline", Pipeline([
        ("select_cat", DataFrameSelector(cat_features)),
        ("cat_encoder", OneHotEncoder(sparse=False)),
    ])),
])

执行full_pipeline.fit_transform(X_train(时，出现以下错误：

ValueError                                Traceback (most recent call last)
<ipython-input-69-6927adc0ed62> in <module>()
     22 ])
     23 
---> 24 full_pipeline.fit_transform(X_train)
/anaconda3/lib/python3.6/site-packages/sklearn/pipeline.py in fit_transform(self, X, y, **fit_params)
    298         Xt, fit_params = self._fit(X, y, **fit_params)
    299         if hasattr(last_step, 'fit_transform'):
--> 300             return last_step.fit_transform(Xt, y, **fit_params)
    301         elif last_step is None:
    302             return Xt
/anaconda3/lib/python3.6/site-packages/sklearn/pipeline.py in fit_transform(self, X, y, **fit_params)
    798         self._update_transformer_list(transformers)
    799         if any(sparse.issparse(f) for f in Xs):
--> 800             Xs = sparse.hstack(Xs).tocsr()
    801         else:
    802             Xs = np.hstack(Xs)
/anaconda3/lib/python3.6/site-packages/scipy/sparse/construct.py in hstack(blocks, format, dtype)
    462 
    463     """
--> 464     return bmat([blocks], format=format, dtype=dtype)
    465 
    466 
/anaconda3/lib/python3.6/site-packages/scipy/sparse/construct.py in bmat(blocks, format, dtype)
    583                                                     exp=brow_lengths[i],
    584                                                     got=A.shape[0]))
--> 585                     raise ValueError(msg)
    586 
    587                 if bcol_lengths[j] == 0:
ValueError: blocks[0,:] has incompatible row dimensions. Got blocks[0,1].shape[0] == 1, expected 19634.

我

无法弄清楚我做错了什么。任何帮助，不胜感激。

Answer 1

所以我通过使用 spicy.sparse 中的 hstack 来连接两个稀疏矩阵来让它工作。请参阅下面的代码：

from scipy.sparse import coo_matrix, hstack
from sklearn.preprocessing import OneHotEncoder
with_prod_tfidf = text_pipeline.fit_transform(with_prod['Text'])
#as per https://stackoverflow.com/questions/19710602/concatenate-sparse-matrices-in-python-using-scipy-numpy
with_prod_all = hstack([with_prod_tfidf, OneHotEncoder().fit_transform(with_prod[cat_features])])
print(with_prod_all.shape)