BUG: Switched shapes in ValueError msg in DataFrame construct (#20742)

doc/source/whatsnew/v0.24.0.rst

@@ -1108,6 +1108,7 @@ update the ``ExtensionDtype._metadata`` tuple to match the signature of your
 - :meth:`~pandas.api.types.ExtensionArray.searchsorted` has been added (:issue:`24350`)
 - Support for reduction operations such as ``sum``, ``mean`` via opt-in base class method override (:issue:`22762`)
 - :func:`ExtensionArray.isna` is allowed to return an ``ExtensionArray`` (:issue:`22325`).
+- Cleanup ``ValueError`` message thrown in creation of block manager: list block shape before number of total items in passed input shape and implied shape. (:issue:`20742`)
 
 **Dtype changes**
 
@@ -1853,6 +1854,7 @@ Other
 
 - Bug where C variables were declared with external linkage causing import errors if certain other C libraries were imported before Pandas. (:issue:`24113`)
 
+
 .. _whatsnew_0.24.0.contributors:
 
 Contributors

pandas/core/internals/managers.py

@@ -1674,7 +1674,13 @@ def create_block_manager_from_arrays(arrays, names, axes):
 def construction_error(tot_items, block_shape, axes, e=None):
     """ raise a helpful message about our construction """
     passed = tuple(map(int, [tot_items] + list(block_shape)))
-    implied = tuple(map(int, [len(ax) for ax in axes]))
+    if len(passed) == 2:
+        passed = passed[::-1]
+
+    implied = tuple(len(ax) for ax in axes)
+    if len(implied) == 2:
+        implied = implied[::-1]
+
     if passed == implied and e is not None:
         raise e
     if block_shape[0] == 0:

pandas/tests/frame/test_constructors.py

@@ -386,25 +386,35 @@ def test_constructor_error_msgs(self):
                        'B': ['a', 'b', 'c']})
 
         # wrong size ndarray, GH 3105
-        msg = r"Shape of passed values is \(3, 4\), indices imply \(3, 3\)"
+        msg = r"Shape of passed values is \(4, 3\), indices imply \(3, 3\)"
         with pytest.raises(ValueError, match=msg):
             DataFrame(np.arange(12).reshape((4, 3)),
                       columns=['foo', 'bar', 'baz'],
                       index=pd.date_range('2000-01-01', periods=3))
 
+        arr = np.array([[4, 5, 6]])
+        msg = r"Shape of passed values is \(1, 3\), indices imply \(1, 4\)"
+        with pytest.raises(ValueError, match=msg):
+            DataFrame(index=[0], columns=range(0, 4), data=arr)
+
+        arr = np.array([4, 5, 6])
+        msg = r"Shape of passed values is \(3, 1\), indices imply \(1, 4\)"
+        with pytest.raises(ValueError, match=msg):
+            DataFrame(index=[0], columns=range(0, 4), data=arr)
+
         # higher dim raise exception
         with pytest.raises(ValueError, match='Must pass 2-d input'):
             DataFrame(np.zeros((3, 3, 3)), columns=['A', 'B', 'C'], index=[1])
 
         # wrong size axis labels
         msg = ("Shape of passed values "
-               r"is \(3, 2\), indices "
-               r"imply \(3, 1\)")
+               r"is \(2, 3\), indices "
+               r"imply \(1, 3\)")
         with pytest.raises(ValueError, match=msg):
             DataFrame(np.random.rand(2, 3), columns=['A', 'B', 'C'], index=[1])
 
         msg = ("Shape of passed values "
-               r"is \(3, 2\), indices "
+               r"is \(2, 3\), indices "
                r"imply \(2, 2\)")
         with pytest.raises(ValueError, match=msg):
             DataFrame(np.random.rand(2, 3), columns=['A', 'B'], index=[1, 2])
@@ -638,10 +648,10 @@ def _check_basic_constructor(self, empty):
         assert frame.values.dtype == np.int64
 
         # wrong size axis labels
-        msg = r'Shape of passed values is \(3, 2\), indices imply \(3, 1\)'
+        msg = r'Shape of passed values is \(2, 3\), indices imply \(1, 3\)'
         with pytest.raises(ValueError, match=msg):
             DataFrame(mat, columns=['A', 'B', 'C'], index=[1])
-        msg = r'Shape of passed values is \(3, 2\), indices imply \(2, 2\)'
+        msg = r'Shape of passed values is \(2, 3\), indices imply \(2, 2\)'
         with pytest.raises(ValueError, match=msg):
             DataFrame(mat, columns=['A', 'B'], index=[1, 2])
 
@@ -1805,7 +1815,7 @@ def test_from_records_to_records(self):
         tm.assert_frame_equal(DataFrame.from_records(arr2), DataFrame(arr2))
 
         # wrong length
-        msg = r'Shape of passed values is \(3, 2\), indices imply \(3, 1\)'
+        msg = r'Shape of passed values is \(2, 3\), indices imply \(1, 3\)'
         with pytest.raises(ValueError, match=msg):
             DataFrame.from_records(arr, index=index[:-1])
 

pandas/tests/io/json/test_pandas.py

@@ -346,7 +346,7 @@ def test_frame_from_json_bad_data(self):
         json = StringIO('{"columns":["A","B"],'
                         '"index":["2","3"],'
                         '"data":[[1.0,"1"],[2.0,"2"],[null,"3"]]}')
-        msg = r"Shape of passed values is \(2, 3\), indices imply \(2, 2\)"
+        msg = r"Shape of passed values is \(3, 2\), indices imply \(2, 2\)"
         with pytest.raises(ValueError, match=msg):
             read_json(json, orient="split")