updated compare error message format

Author: tpackard1

pandas/core/ops/__init__.py

@@ -313,7 +313,7 @@ def to_series(right):
                 left, right = left.align(right, join="outer", level=level, copy=False)
             else:
                 raise ValueError(
-                    "Can only compare identically-labeled (both index and columns)"
+                    "Can only compare identically-labeled (both index and columns) "
                     "DataFrame objects"
                 )
     elif isinstance(right, ABCSeries):

pandas/tests/frame/methods/test_compare.py

@@ -171,7 +171,7 @@ def test_compare_multi_index(align_axis):
 def test_compare_unaligned_objects():
     # test DataFrames with different indices
     msg = (
-        "Can only compare identically-labeled (both index and columns) DataFrame"
+        "Can only compare identically-labeled (both index and columns) DataFrame "
         "objects"
     )
     with pytest.raises(ValueError, match=msg):
@@ -181,7 +181,7 @@ def test_compare_unaligned_objects():
 
     # test DataFrames with different shapes
     msg = (
-        "Can only compare identically-labeled (both index and columns) DataFrame"
+        "Can only compare identically-labeled (both index and columns) DataFrame "
         "objects"
     )
     with pytest.raises(ValueError, match=msg):

pandas/tests/frame/test_arithmetic.py

@@ -1537,7 +1537,7 @@ def test_comparisons(self, simple_frame, float_frame, func):
         tm.assert_numpy_array_equal(result3.values, func(float_frame.values, 0))
 
         msg = (
-            "Can only compare identically-labeled (both index and columns)"
+            "Can only compare identically-labeled (both index and columns) "
             "DataFrame objects"
         )
         with pytest.raises(ValueError, match=msg):

pandas/tests/frame/test_nonunique_indexes.py

@@ -204,7 +204,7 @@ def test_dup_columns_comparisons(self):
 
         # not-comparing like-labelled
         msg = (
-            "Can only compare identically-labeled (both index and columns)"
+            "Can only compare identically-labeled (both index and columns) "
             "DataFrame objects"
         )
         with pytest.raises(ValueError, match=msg):

pandas/tests/series/test_arithmetic.py

@@ -627,14 +627,14 @@ def test_comp_ops_df_compat(self, left, right, frame_or_series):
         # GH 50083 to clarify that index and columns must be identically labeled
         if frame_or_series is not Series:
             msg = (
-                f"Can only compare identically-labeled (both index and columns)"
+                f"Can only compare identically-labeled (both index and columns) "
                 f"{frame_or_series.__name__} objects"
             )
             left = left.to_frame()
             right = right.to_frame()
         else:
             msg = (
-                f"Can only compare identically-labeled {frame_or_series.__name__}"
+                f"Can only compare identically-labeled {frame_or_series.__name__} "
                 f"objects"
             )
         with pytest.raises(ValueError, match=msg):