REF: put concatenate_block_managers in internals.concat (pandas-dev#33231)

Author: jbrockmendel

pandas/core/internals/__init__.py

@@ -14,11 +14,8 @@
     _safe_reshape,
     make_block,
 )
-from pandas.core.internals.managers import (
-    BlockManager,
-    SingleBlockManager,
-    concatenate_block_managers,
-)
+from pandas.core.internals.concat import concatenate_block_managers
+from pandas.core.internals.managers import BlockManager, SingleBlockManager
 
 __all__ = [
     "Block",

pandas/core/internals/concat.py

@@ -23,9 +23,57 @@
 from pandas.core.dtypes.missing import isna
 
 import pandas.core.algorithms as algos
+from pandas.core.internals.blocks import make_block
+from pandas.core.internals.managers import BlockManager
 
 
-def get_mgr_concatenation_plan(mgr, indexers):
+def concatenate_block_managers(
+    mgrs_indexers, axes, concat_axis: int, copy: bool
+) -> BlockManager:
+    """
+    Concatenate block managers into one.
+
+    Parameters
+    ----------
+    mgrs_indexers : list of (BlockManager, {axis: indexer,...}) tuples
+    axes : list of Index
+    concat_axis : int
+    copy : bool
+
+    Returns
+    -------
+    BlockManager
+    """
+    concat_plans = [
+        _get_mgr_concatenation_plan(mgr, indexers) for mgr, indexers in mgrs_indexers
+    ]
+    concat_plan = _combine_concat_plans(concat_plans, concat_axis)
+    blocks = []
+
+    for placement, join_units in concat_plan:
+
+        if len(join_units) == 1 and not join_units[0].indexers:
+            b = join_units[0].block
+            values = b.values
+            if copy:
+                values = values.copy()
+            else:
+                values = values.view()
+            b = b.make_block_same_class(values, placement=placement)
+        elif _is_uniform_join_units(join_units):
+            b = join_units[0].block.concat_same_type([ju.block for ju in join_units])
+            b.mgr_locs = placement
+        else:
+            b = make_block(
+                _concatenate_join_units(join_units, concat_axis, copy=copy),
+                placement=placement,
+            )
+        blocks.append(b)
+
+    return BlockManager(blocks, axes)
+
+
+def _get_mgr_concatenation_plan(mgr, indexers):
     """
     Construct concatenation plan for given block manager and indexers.
 
@@ -232,7 +280,7 @@ def get_reindexed_values(self, empty_dtype, upcasted_na):
         return values
 
 
-def concatenate_join_units(join_units, concat_axis, copy):
+def _concatenate_join_units(join_units, concat_axis, copy):
     """
     Concatenate values from several join units along selected axis.
     """
@@ -371,11 +419,11 @@ def _get_empty_dtype_and_na(join_units):
     raise AssertionError(msg)
 
 
-def is_uniform_join_units(join_units) -> bool:
+def _is_uniform_join_units(join_units) -> bool:
     """
     Check if the join units consist of blocks of uniform type that can
     be concatenated using Block.concat_same_type instead of the generic
-    concatenate_join_units (which uses `concat_compat`).
+    _concatenate_join_units (which uses `concat_compat`).
 
     """
     return (
@@ -429,7 +477,7 @@ def _trim_join_unit(join_unit, length):
     return JoinUnit(block=extra_block, indexers=extra_indexers, shape=extra_shape)
 
 
-def combine_concat_plans(plans, concat_axis):
+def _combine_concat_plans(plans, concat_axis):
     """
     Combine multiple concatenation plans into one.
 

pandas/core/internals/managers.py

@@ -47,12 +47,6 @@
     get_block_type,
     make_block,
 )
-from pandas.core.internals.concat import (  # all for concatenate_block_managers
-    combine_concat_plans,
-    concatenate_join_units,
-    get_mgr_concatenation_plan,
-    is_uniform_join_units,
-)
 
 from pandas.io.formats.printing import pprint_thing
 
@@ -1974,44 +1968,3 @@ def _preprocess_slice_or_indexer(slice_or_indexer, length, allow_fill):
         if not allow_fill:
             indexer = maybe_convert_indices(indexer, length)
         return "fancy", indexer, len(indexer)
-
-
-def concatenate_block_managers(mgrs_indexers, axes, concat_axis, copy):
-    """
-    Concatenate block managers into one.
-
-    Parameters
-    ----------
-    mgrs_indexers : list of (BlockManager, {axis: indexer,...}) tuples
-    axes : list of Index
-    concat_axis : int
-    copy : bool
-
-    """
-    concat_plans = [
-        get_mgr_concatenation_plan(mgr, indexers) for mgr, indexers in mgrs_indexers
-    ]
-    concat_plan = combine_concat_plans(concat_plans, concat_axis)
-    blocks = []
-
-    for placement, join_units in concat_plan:
-
-        if len(join_units) == 1 and not join_units[0].indexers:
-            b = join_units[0].block
-            values = b.values
-            if copy:
-                values = values.copy()
-            else:
-                values = values.view()
-            b = b.make_block_same_class(values, placement=placement)
-        elif is_uniform_join_units(join_units):
-            b = join_units[0].block.concat_same_type([ju.block for ju in join_units])
-            b.mgr_locs = placement
-        else:
-            b = make_block(
-                concatenate_join_units(join_units, concat_axis, copy=copy),
-                placement=placement,
-            )
-        blocks.append(b)
-
-    return BlockManager(blocks, axes)