Used object() in check_X_y to check for sample_weight

kaichogami · kaichogami · commit 89b7e9a32728 · 2016-02-19T13:06:07.000+05:30
diff --git a/sklearn/utils/validation.py b/sklearn/utils/validation.py
@@ -21,6 +21,8 @@
 from ..exceptions import NonBLASDotWarning as _NonBLASDotWarning
 from ..exceptions import NotFittedError as _NotFittedError
 
+NOT_SPECIFIED = object()
+
 
 @deprecated("DataConversionWarning has been moved into the sklearn.exceptions"
             " module. It will not be available here from version 0.19")
@@ -429,7 +431,7 @@ def check_X_y(X, y, accept_sparse=None, dtype="numeric", order=None,
               copy=False, force_all_finite=True, ensure_2d=True,
               allow_nd=False, multi_output=False, ensure_min_samples=1,
               ensure_min_features=1, y_numeric=False,
-              warn_on_dtype=False, estimator=None, sample_weight=False):
+              warn_on_dtype=False, estimator=None, sample_weight=NOT_SPECIFIED):
     """Input validation for standard estimators.
 
     Checks X and y for consistent length, enforces X 2d and y 1d.
@@ -503,6 +505,10 @@ def check_X_y(X, y, accept_sparse=None, dtype="numeric", order=None,
     estimator : str or estimator instance (default=None)
         If passed, include the name of the estimator in warning messages.
 
+    sample_weight : nd-array, list
+        Ensures sample_weight is 1-d.
+        
+
     Returns
     -------
     X_converted : object
@@ -525,16 +531,17 @@ def check_X_y(X, y, accept_sparse=None, dtype="numeric", order=None,
 
     check_consistent_length(X, y)
 
-    if sample_weight is None:
+    if sample_weight is NOT_SPECIFIED:
+        return X, y
+
+    elif sample_weight is None:
         return X, y, sample_weight
 
-    elif sample_weight is not False:
+    else:
         sample_weight = check_array(sample_weight, ensure_2d=False)
         check_consistent_length(y, sample_weight)
         return X, y, sample_weight
 
-    return X, y
-
 
 def column_or_1d(y, warn=False):
     """ Ravel column or 1d numpy array, else raises an error
