如何在管道中使用 SMOTENC(错误:某些分类索引超出范围)

Question

如果您能告诉我如何使用 SMOTENC，我将不胜感激。 我写道：

# Data
XX = pd.read_csv('Financial Distress.csv')
y = np.array(XX['Financial Distress'].values.tolist())
y = np.array([0 if i > -0.50 else 1 for i in y])
Na = np.array(pd.read_csv('Na.csv', header=None).values)
XX = XX.iloc[:, 3:127]
# Use get-dummies to convert categorical features into dummy ones
dis_features = ['x121']
X = pd.get_dummies(XX, columns=dis_features)
# # Divide Data into Train and Test
indices = np.arange(y.shape[0])
X_train, X_test, y_train, y_test, idx_train, idx_test = train_test_split(X, y, indices, stratify=y, test_size=0.3,
                                                                         random_state=42)
num_indices=list(X)[:X.shape[1]-37]
cat_indices=list(X)[X.shape[1]-37:]
num_indices1 = list(X.iloc[:,np.r_[0:94,95,97,100:123]].columns.values)
cat_indices1 = list(X.iloc[:,np.r_[94,96,98,99,123:160]].columns.values)
print(len(num_indices1))
print(len(cat_indices1))
pipeline=Pipeline(steps= [
    # Categorical features
    ('feature_processing', FeatureUnion(transformer_list = [
            ('categorical', MultiColumn(cat_indices)),
            #numeric
            ('numeric', Pipeline(steps = [
                ('select', MultiColumn(num_indices)),
                ('scale', StandardScaler())
                        ]))
        ])),
    ('clf', rg)
    ]
)
pipeline_with_resampling = make_pipeline(SMOTENC(categorical_features=cat_indices1), pipeline)
# # Grid Search to determine best params
cv=StratifiedKFold(n_splits=5,random_state=42)
rg_cv = GridSearchCV(pipeline_with_resampling, param_grid, cv=cv, scoring = 'f1')
rg_cv.fit(X_train, y_train)

因此，如前所述，我有 5 个分类特征。实际上，索引 123 到 160 与一个具有 37 个可能值的分类特征相关，该特征使用 get_dummies 转换为 37 列。不幸的是，它抛出以下错误：

Traceback (most recent call last):
  File "D:/mifs-master_2/MU/learning-from-imbalanced-classes-master/learning-from-imbalanced-classes-master/continuous/Final Logit/SMOTENC/logit-final - Copy.py", line 424, in <module>
    rg_cv.fit(X_train, y_train)
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnmodel_selection_search.py", line 722, in fit
    self._run_search(evaluate_candidates)
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnmodel_selection_search.py", line 1191, in _run_search
    evaluate_candidates(ParameterGrid(self.param_grid))
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnmodel_selection_search.py", line 711, in evaluate_candidates
    cv.split(X, y, groups)))
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnexternalsjoblibparallel.py", line 917, in __call__
    if self.dispatch_one_batch(iterator):
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnexternalsjoblibparallel.py", line 759, in dispatch_one_batch
    self._dispatch(tasks)
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnexternalsjoblibparallel.py", line 716, in _dispatch
    job = self._backend.apply_async(batch, callback=cb)
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnexternalsjoblib_parallel_backends.py", line 182, in apply_async
    result = ImmediateResult(func)
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnexternalsjoblib_parallel_backends.py", line 549, in __init__
    self.results = batch()
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnexternalsjoblibparallel.py", line 225, in __call__
    for func, args, kwargs in self.items]
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnexternalsjoblibparallel.py", line 225, in <listcomp>
    for func, args, kwargs in self.items]
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnmodel_selection_validation.py", line 528, in _fit_and_score
    estimator.fit(X_train, y_train, **fit_params)
  File "C:UsersMarkazi.coAnaconda3libsite-packagesimblearnpipeline.py", line 237, in fit
    Xt, yt, fit_params = self._fit(X, y, **fit_params)
  File "C:UsersMarkazi.coAnaconda3libsite-packagesimblearnpipeline.py", line 200, in _fit
    cloned_transformer, Xt, yt, **fit_params_steps[name])
  File "C:UsersMarkazi.coAnaconda3libsite-packagessklearnexternalsjoblibmemory.py", line 342, in __call__
    return self.func(*args, **kwargs)
  File "C:UsersMarkazi.coAnaconda3libsite-packagesimblearnpipeline.py", line 576, in _fit_resample_one
    X_res, y_res = sampler.fit_resample(X, y, **fit_params)
  File "C:UsersMarkazi.coAnaconda3libsite-packagesimblearnbase.py", line 85, in fit_resample
    output = self._fit_resample(X, y)
  File "C:UsersMarkazi.coAnaconda3libsite-packagesimblearnover_sampling_smote.py", line 940, in _fit_resample
    self._validate_estimator()
  File "C:UsersMarkazi.coAnaconda3libsite-packagesimblearnover_sampling_smote.py", line 933, in _validate_estimator
    ' should be between 0 and {}'.format(self.n_features_))
ValueError: Some of the categorical indices are out of range. Indices should be between 0 and 160

提前谢谢。

Answer 1

如下所示，应使用两个管道：

num_indices1 = list(X.iloc[:,np.r_[0:94,95,97,100:120,121:123]].columns.values)
cat_indices1 = list(X.iloc[:,np.r_[94,96,98,99,120]].columns.values)
print(len(num_indices1))
print(len(cat_indices1))
cat_indices = [94, 96, 98, 99, 120]
from imblearn.pipeline import make_pipeline
pipeline=Pipeline(steps= [
    # Categorical features
    ('feature_processing', FeatureUnion(transformer_list = [
            ('categorical', MultiColumn(cat_indices1)),
            #numeric
            ('numeric', Pipeline(steps = [
                ('select', MultiColumn(num_indices1)),
                ('scale', StandardScaler())
                        ]))
        ])),
    ('clf', rg)
    ]
)
pipeline_with_resampling = make_pipeline(SMOTENC(categorical_features=cat_indices), pipeline)

Answer 2

你不能假化

你的分类变量并在以后使用它 SMOTENC，因为它已经在其算法中实现了什么会偏向你的模型get_dummies。但是，我建议使用SMOTE（）而不是SMOTENC（），但在这种情况下，您必须首先应用get_demmies。

Answer 3

您不能将scikit learn管道与imblearn管道一起使用。imblearn 管道实现了fit_sample和fit_predict。Sklearn pipeline onle 实现fit_predict。您不能将它们组合在一起。

Answer 4

首先，不要做get_dummies。然后，改变你做categorical_features的方式，并列出布尔值列表，看看它是否是绝对的。

试试这个：

cat_cols = []
for col in x.columns:
    if x[col].dtype == 'object': #or 'category' if that's the case
        cat_cols.append(True)
    else:
        cat_cols.append(False)

然后将cat_cols传递给您的 SMOTENC：

smote_nc = SMOTENC(categorical_features=cat_cols, random_state=0)