REF: collect attribute-setting at the end of create_axes (pandas-dev#30029)

Author: jbrockmendel

pandas/io/pytables.py

@@ -3734,7 +3734,7 @@ def read_axes(
 
         return True
 
-    def get_object(self, obj):
+    def get_object(self, obj, transposed: bool):
         """ return the data for this obj """
         return obj
 
@@ -3838,15 +3838,13 @@ def create_axes(
             )
 
         # create according to the new data
-        self.non_index_axes = []
-        self.data_columns = []
+        new_non_index_axes: List = []
+        new_data_columns: List[Optional[str]] = []
 
         # nan_representation
         if nan_rep is None:
             nan_rep = "nan"
 
-        self.nan_rep = nan_rep
-
         # create axes to index and non_index
         index_axes_map = dict()
         for i, a in enumerate(obj.axes):
@@ -3863,7 +3861,7 @@ def create_axes(
                 # necessary
                 append_axis = list(a)
                 if existing_table is not None:
-                    indexer = len(self.non_index_axes)
+                    indexer = len(new_non_index_axes)
                     exist_axis = existing_table.non_index_axes[indexer][1]
                     if not array_equivalent(
                         np.array(append_axis), np.array(exist_axis)
@@ -3880,34 +3878,37 @@ def create_axes(
                 info["names"] = list(a.names)
                 info["type"] = type(a).__name__
 
-                self.non_index_axes.append((i, append_axis))
+                new_non_index_axes.append((i, append_axis))
+
+        self.non_index_axes = new_non_index_axes
 
         # set axis positions (based on the axes)
         new_index_axes = [index_axes_map[a] for a in axes]
         for j, iax in enumerate(new_index_axes):
             iax.set_pos(j)
             iax.update_info(self.info)
-        self.index_axes = new_index_axes
 
-        j = len(self.index_axes)
+        j = len(new_index_axes)
 
         # check for column conflicts
-        for a in self.axes:
+        for a in new_index_axes:
             a.maybe_set_size(min_itemsize=min_itemsize)
 
         # reindex by our non_index_axes & compute data_columns
-        for a in self.non_index_axes:
+        for a in new_non_index_axes:
             obj = _reindex_axis(obj, a[0], a[1])
 
         def get_blk_items(mgr, blocks):
             return [mgr.items.take(blk.mgr_locs) for blk in blocks]
 
+        transposed = new_index_axes[0].axis == 1
+
         # figure out data_columns and get out blocks
-        block_obj = self.get_object(obj)._consolidate()
+        block_obj = self.get_object(obj, transposed)._consolidate()
         blocks = block_obj._data.blocks
         blk_items = get_blk_items(block_obj._data, blocks)
-        if len(self.non_index_axes):
-            axis, axis_labels = self.non_index_axes[0]
+        if len(new_non_index_axes):
+            axis, axis_labels = new_non_index_axes[0]
             data_columns = self.validate_data_columns(data_columns, min_itemsize)
             if len(data_columns):
                 mgr = block_obj.reindex(
@@ -3945,7 +3946,7 @@ def get_blk_items(mgr, blocks):
             blk_items = new_blk_items
 
         # add my values
-        self.values_axes = []
+        vaxes = []
         for i, (b, b_items) in enumerate(zip(blocks, blk_items)):
 
             # shape of the data column are the indexable axes
@@ -3959,7 +3960,7 @@ def get_blk_items(mgr, blocks):
                 if not (name is None or isinstance(name, str)):
                     # TODO: should the message here be more specifically non-str?
                     raise ValueError("cannot have non-object label DataIndexableCol")
-                self.data_columns.append(name)
+                new_data_columns.append(name)
 
             # make sure that we match up the existing columns
             # if we have an existing table
@@ -3987,10 +3988,15 @@ def get_blk_items(mgr, blocks):
             )
             col.set_pos(j)
 
-            self.values_axes.append(col)
+            vaxes.append(col)
 
             j += 1
 
+        self.nan_rep = nan_rep
+        self.data_columns = new_data_columns
+        self.values_axes = vaxes
+        self.index_axes = new_index_axes
+
         # validate our min_itemsize
         self.validate_min_itemsize(min_itemsize)
 
@@ -4428,9 +4434,9 @@ class AppendableFrameTable(AppendableTable):
     def is_transposed(self) -> bool:
         return self.index_axes[0].axis == 1
 
-    def get_object(self, obj):
+    def get_object(self, obj, transposed: bool):
         """ these are written transposed """
-        if self.is_transposed:
+        if transposed:
             obj = obj.T
         return obj
 
@@ -4512,7 +4518,7 @@ class AppendableSeriesTable(AppendableFrameTable):
     def is_transposed(self) -> bool:
         return False
 
-    def get_object(self, obj):
+    def get_object(self, obj, transposed: bool):
         return obj
 
     def write(self, obj, data_columns=None, **kwargs):