Merge pull request #393 from pimlock/fix-basen-inverse-transform

Fix basen_to_integer when column name contains regex metachar

Author: PaulWestenthanner

category_encoders/basen.py

@@ -266,7 +266,7 @@ def basen_to_integer(self, X, cols, base):
         out_cols = X.columns.values.tolist()
 
         for col in cols:
-            col_list = [col0 for col0 in out_cols if re.match(str(col)+'_\\d+', str(col0))]
+            col_list = [col0 for col0 in out_cols if re.match(re.escape(str(col))+'_\\d+', str(col0))]
             insert_at = out_cols.index(col_list[0])
 
             if base == 1:

tests/test_basen.py

@@ -140,6 +140,16 @@ def test_inverse_transform_HaveHandleMissingValueAndHandleUnknownReturnNan_Expec
 
         pd.testing.assert_frame_equal(expected, original)
 
+    def test_inverse_transform_HaveRegexMetacharactersInColumnName_ExpectInversed(self):
+        train = pd.DataFrame({'state (2-letter code)': ['il', 'ny', 'ca']})
+
+        enc = encoders.BaseNEncoder()
+        enc.fit(train)
+        result = enc.transform(train)
+        original = enc.inverse_transform(result)
+
+        pd.testing.assert_frame_equal(train, original)
+
     def test_num_cols(self):
         """
         Test that BaseNEncoder produces the correct number of output columns.