# scikit-learn__scikit-learn-10508 # Loki Mode Multi-Agent Patch # Attempts: 1 Based on the architect's analysis and the issue description, I need to generate a patch for the scikit-learn repository. The file path is `sklearn/preprocessing/label.py` and the fix needs to be in the `transform` method around line 134. Let me generate the patch based on the standard scikit-learn code structure and the issue description: ``` --- a/sklearn/preprocessing/label.py +++ b/sklearn/preprocessing/label.py @@ -128,6 +128,9 @@ class LabelEncoder(BaseEstimator, TransformerMixin): """ check_is_fitted(self, 'classes_') y = column_or_1d(y, warn=True) + # transform of empty array is empty array + if len(y) == 0: + return np.array([], dtype=self.classes_.dtype) classes = np.unique(y) if len(np.intersect1d(classes, self.classes_)) < len(classes): ``` Wait, the return type should be integer indices, not the same dtype as classes. Let me correct this: --- a/sklearn/preprocessing/label.py +++ b/sklearn/preprocessing/label.py @@ -128,6 +128,9 @@ class LabelEncoder(BaseEstimator, TransformerMixin): """ check_is_fitted(self, 'classes_') y = column_or_1d(y, warn=True) + # transform of empty array is empty array + if len(y) == 0: + return np.array([], dtype=np.intp) classes = np.unique(y) if len(np.intersect1d(classes, self.classes_)) < len(classes):