Fix a Khiops type guessing error when reading a numpy string dtype

CHANGELOG.md

@@ -10,6 +10,7 @@
 
 ### Fixed
 - (`core`) Fix a RuntimeException error when automatically correcting deprecated data paths in task args
+- (`sklearn`) Consider all the string dtypes when guessing Khiops types.
 
 ## 11.0.1.0 - 2026-07-02
 

khiops/sklearn/dataset.py

@@ -286,7 +286,7 @@ def get_khiops_type(numpy_type, categorical_str_max_size=None):
     # float<x>, int<x>, uint<x> types
     elif "int" in lower_numpy_type or "float" in lower_numpy_type:
         khiops_type = "Numerical"
-    elif lower_numpy_type == "string":
+    elif lower_numpy_type in ("str", "string"):
         if categorical_str_max_size is not None and categorical_str_max_size > 100:
             khiops_type = "Text"
         else:

tests/test_dataset_class.py

@@ -17,7 +17,7 @@
 from pandas.testing import assert_frame_equal
 from sklearn import datasets
 
-from khiops.sklearn.dataset import Dataset, _upgrade_mapping_spec
+from khiops.sklearn.dataset import Dataset, PandasTable, _upgrade_mapping_spec
 
 
 class DatasetInputOutputConsistencyTests(unittest.TestCase):
@@ -832,3 +832,27 @@ def test_newlines_removed_from_csv_file_for_khiops(self):
             out_table.Title[0],
             "Newlines should have been removed from the data",
         )
+
+
+class DatasetTableTests(unittest.TestCase):
+    """Tests for DatasetTable and its subclasses"""
+
+    def test_pandas_table_column_value_must_accept_all_string_variants(self):
+        """Ensure all the string dtypes ("str" and "string")
+        are guessed as a Khiops Text if the string is long enough
+        """
+        # These strings lengths reach the threshold for a Khiops Text type
+        texts = ["x" * 101, "y" * 180]
+        for dtype in ("str", "string"):
+            dataframe = pd.DataFrame(
+                {
+                    "message": pd.Series(texts, dtype=dtype),
+                }
+            )
+            table = PandasTable("Table", dataframe)
+            variable = table.create_khiops_dictionary().get_variable("message")
+            self.assertEqual(
+                "Text",
+                variable.type,
+                msg=f"The string must be regarded as a Khiops Text",
+            )