CLN: rename Block.ref_locs -> mgr_locs to reduce confusion

PERF: add BlockPlacement class to optimize range-like cases

CLN: unify get_slice & take/reindex ops along axis0

TST: add slicing/taking/reindexing tests for BlockManagers

CLN: remove unused code

Author: immerrr

pandas/computation/tests/test_eval.py

@@ -1292,7 +1292,7 @@ def _save_chunk(self, start_i, end_i):
                                   float_format=self.float_format,
                                   date_format=self.date_format)
 
-            for col_loc, col in zip(b.ref_locs, d):
+            for col_loc, col in zip(b.mgr_locs, d):
                 # self.data is a preallocated list
                 self.data[col_loc] = col
 

pandas/core/format.py

@@ -1045,7 +1045,7 @@ def to_panel(self):
         for block in selfsorted._data.blocks:
             newb = block2d_to_blocknd(
                 values=block.values.T,
-                placement=block.ref_locs, shape=shape,
+                placement=block.mgr_locs, shape=shape,
                 labels=[major_labels, minor_labels],
                 ref_items=selfsorted.columns)
             new_blocks.append(newb)

pandas/core/frame.py

@@ -1689,7 +1689,7 @@ def reindex_axis(self, labels, axis=0, method=None, level=None, copy=True,
             labels, method, level, limit=limit, copy_if_needed=True)
         return self._reindex_with_indexers(
             {axis: [new_index, indexer]}, method=method, fill_value=fill_value,
-            limit=limit, copy=copy).__finalize__(self)
+            limit=limit, copy=copy)
 
     def _reindex_with_indexers(self, reindexers, method=None,
                                fill_value=np.nan, limit=None, copy=False,
@@ -1712,7 +1712,8 @@ def _reindex_with_indexers(self, reindexers, method=None,
             # TODO: speed up on homogeneous DataFrame objects
             new_data = new_data.reindex_indexer(index, indexer, axis=baxis,
                                                 fill_value=fill_value,
-                                                allow_dups=allow_dups)
+                                                allow_dups=allow_dups,
+                                                copy=copy)
 
         if copy and new_data is self._data:
             new_data = new_data.copy()

pandas/core/generic.py

@@ -2243,7 +2243,7 @@ def _cython_agg_blocks(self, how, numeric_only=True):
             # see if we can cast the block back to the original dtype
             result = block._try_cast_result(result)
 
-            newb = make_block(result, placement=block.ref_locs)
+            newb = make_block(result, placement=block.mgr_locs)
             new_blocks.append(newb)
 
         if len(new_blocks) == 0: