在 sklearn 中将 DataFrameMapper() 用于 PolynomialFeature() 时出错

Error in using DataFrameMapper() for PolynomialFeature() in sklearn

对于 housing data set,我正在尝试使用 sklearn_pandas 中的 DataFrameMapper() 在所选列上应用多项式特征。

我的代码:

 from sklearn.preprocessing import PolynomialFeatures
 from sklearn_pandas import DataFrameMapper

 mapper = DataFrameMapper([
('houseAge_income', PolynomialFeatures(2)),
('median_income', PolynomialFeatures(2)),
(['latitude', 'housing_median_age', 'total_rooms', 'population', 'median_house_value', 
'ocean_proximity']], None)
 ])

 poly_feature = mapper.fit_transform(housing) 

我遇到了这个错误:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-44-30679ae791ae> in <module>
     11 
     12 # fit
---> 13 poly_feature = mapper.fit_transform(df)

e:\Anaconda3\lib\site-packages\sklearn_pandas\dataframe_mapper.py in fit_transform(self, X, y)
    397         y       the target vector relative to X, optional
    398         """
--> 399         return self._transform(X, y, True)

e:\Anaconda3\lib\site-packages\sklearn_pandas\dataframe_mapper.py in _transform(self, X, y, do_fit)
    308                 with add_column_names_to_exception(columns):
    309                     if do_fit and hasattr(transformers, 'fit_transform'):
--> 310                         Xt = _call_fit(transformers.fit_transform, Xt, y)
    311                     else:
    312                         if do_fit:

e:\Anaconda3\lib\site-packages\sklearn_pandas\pipeline.py in _call_fit(fit_method, X, y, **kwargs)
     22     """
     23     try:
---> 24         return fit_method(X, y, **kwargs)
     25     except TypeError:
     26         # fit takes only one argument

e:\Anaconda3\lib\site-packages\sklearn\base.py in fit_transform(self, X, y, **fit_params)
    688         if y is None:
    689             # fit method of arity 1 (unsupervised transformation)
--> 690             return self.fit(X, **fit_params).transform(X)
    691         else:
    692             # fit method of arity 2 (supervised transformation)

e:\Anaconda3\lib\site-packages\sklearn\preprocessing\_data.py in fit(self, X, y)
   1510         self : instance
   1511         """
-> 1512         n_samples, n_features = self._validate_data(
   1513             X, accept_sparse=True).shape
   1514         combinations = self._combinations(n_features, self.degree,

e:\Anaconda3\lib\site-packages\sklearn\base.py in _validate_data(self, X, y, reset, validate_separately, **check_params)
    418                     f"requires y to be passed, but the target y is None."
    419                 )
--> 420             X = check_array(X, **check_params)
    421             out = X
    422         else:

e:\Anaconda3\lib\site-packages\sklearn\utils\validation.py in inner_f(*args, **kwargs)
     70                           FutureWarning)
     71         kwargs.update({k: arg for k, arg in zip(sig.parameters, args)})
---> 72         return f(**kwargs)
     73     return inner_f
     74 

e:\Anaconda3\lib\site-packages\sklearn\utils\validation.py in check_array(array, accept_sparse, accept_large_sparse, dtype, order, copy, force_all_finite, ensure_2d, allow_nd, ensure_min_samples, ensure_min_features, estimator)
    617             # If input is 1D raise error
    618             if array.ndim == 1:
--> 619                 raise ValueError(
    620                     "Expected 2D array, got 1D array instead:\narray={}.\n"
    621                     "Reshape your data either using array.reshape(-1, 1) if "

ValueError: houseAge_income: Expected 2D array, got 1D array instead:
array=[341.3332 174.3294 377.3848 ...  28.9     33.6096  38.2176].
Reshape your data either using array.reshape(-1, 1) if your data has a single feature or array.reshape(1, -1) if it contains a single sample.

当我尝试使用

houseAge_income.reshape(-1, 1)

在 DataFrameMapper() 中,我遇到了另一个问题:

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
/usr/local/lib/python3.6/dist-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   2645             try:
-> 2646                 return self._engine.get_loc(key)
   2647             except KeyError:

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 'houseAge_income.reshape(-1, 1)'

During handling of the above exception, another exception occurred:

KeyError                                  Traceback (most recent call last)
5 frames
/usr/local/lib/python3.6/dist-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   2646                 return self._engine.get_loc(key)
   2647             except KeyError:
-> 2648                 return self._engine.get_loc(self._maybe_cast_indexer(key))
   2649         indexer = self.get_indexer([key], method=method, tolerance=tolerance)
   2650         if indexer.ndim > 1 or indexer.size > 1:

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()


pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 'houseAge_income.reshape(-1, 1)'

谁能告诉我,我错过了什么?

我知道形状有问题但无法弄清楚。 没有帮助。

注意:houseAge_income 是由

创建的交互项
housing['houseAge_income'] = housing['housing_median_age']*housing['median_income']
  • 来自documentation
    • 将列选择器指定为 'column'(作为简单字符串)和 ['column'](作为具有一个元素的列表)之间的区别在于数组的形状传递给变压器。在第一种情况下,将传递一个一维数组,而在第二种情况下,它将传递一个具有一列的二维数组,即列向量。
  • 必须使用相同类型的列选择器传递所有列。
    • 在本例中,list,因为要保留 list 个 non-transformed 列。
import pandas as pd
from sklearn.preprocessing import PolynomialFeatures
from sklearn_pandas import DataFrameMapper

# load data
df = pd.read_csv('https://raw.githubusercontent.com/ageron/handson-ml2/master/datasets/housing/housing.csv')

# create houseAge_income
df['houseAge_income'] = df.housing_median_age.mul(df.median_income)

# configure mapper with all columns passed as lists
mapper = DataFrameMapper([(['houseAge_income'], PolynomialFeatures(2)),
                          (['median_income'], PolynomialFeatures(2)),
                          (['latitude', 'housing_median_age', 'total_rooms', 'population', 'median_house_value', 'ocean_proximity'], None)])

# fit
poly_feature = mapper.fit_transform(df)

# display(pd.DataFrame(poly_feature).head())
  0       1           2  3       4       5      6   7     8     9          10        11
0  1  341.33  1.1651e+05  1  8.3252  69.309  37.88  41   880   322  4.526e+05  NEAR BAY
1  1  174.33       30391  1  8.3014  68.913  37.86  21  7099  2401  3.585e+05  NEAR BAY
2  1  377.38  1.4242e+05  1  7.2574   52.67  37.85  52  1467   496  3.521e+05  NEAR BAY
3  1  293.44       86108  1  5.6431  31.845  37.85  52  1274   558  3.413e+05  NEAR BAY
4  1     200       40001  1  3.8462  14.793  37.85  52  1627   565  3.422e+05  NEAR BAY