Review

python/cudf/cudf/core/frame.py

@@ -20,6 +20,7 @@
 from cudf import _lib as libcudf
 from cudf._typing import ColumnLike, DataFrameOrSeries
 from cudf.core.column import as_column, build_categorical_column, column_empty
+from cudf.core.join import merge
 from cudf.utils.dtypes import (
     is_categorical_dtype,
     is_column_like,
@@ -3364,7 +3365,7 @@ def _merge(
             left_index, right_index = right_index, left_index
             suffixes = (suffixes[1], suffixes[0])
 
-        return cudf.core.join.merge(
+        return merge(
             lhs,
             rhs,
             on=on,

python/cudf/cudf/core/join/_join_helpers.py

@@ -200,7 +200,3 @@ def _coerce_to_tuple(obj):
         return tuple(obj)
     else:
         return (obj,)
-
-
-def _coerce_to_list(obj):
-    return list(_coerce_to_tuple(obj))

python/cudf/cudf/core/join/join.py

@@ -2,13 +2,12 @@
 from __future__ import annotations
 
 import functools
-from collections import OrderedDict, namedtuple
+from collections import namedtuple
 from typing import TYPE_CHECKING, Callable, Tuple
 
 import cudf
 from cudf import _lib as libcudf
 from cudf.core.join._join_helpers import (
-    _coerce_to_list,
     _coerce_to_tuple,
     _frame_select_by_indexers,
     _Indexer,
@@ -275,8 +274,8 @@ def _merge_results(self, left_result: Frame, right_result: Frame) -> Frame:
         # Compute the result column names:
         # left_names and right_names will be a mappings of input column names
         # to the corresponding names in the final result.
-        left_names = OrderedDict(zip(left_result._data, left_result._data))
-        right_names = OrderedDict(zip(right_result._data, right_result._data))
+        left_names = dict(zip(left_result._data, left_result._data))
+        right_names = dict(zip(right_result._data, right_result._data))
 
         # For any columns from left_result and right_result that have the same
         # name:
@@ -288,12 +287,14 @@ def _merge_results(self, left_result: Frame, right_result: Frame) -> Frame:
         if self.on:
             key_columns_with_same_name = self.on
         else:
-            key_columns_with_same_name = []
-            for lkey, rkey in zip(*self._keys):
-                if (lkey.index, rkey.index) == (False, False):
-                    if lkey.name == rkey.name:
-                        key_columns_with_same_name.append(lkey.name)
-
+            key_columns_with_same_name = [
+                lkey.name
+                for lkey, rkey in zip(*self._keys)
+                if (
+                    (lkey.index, rkey.index) == (False, False)
+                    and lkey.name == rkey.name
+                )
+            ]
         for name in common_names:
             if name not in key_columns_with_same_name:
                 left_names[name] = f"{name}{self.lsuffix}"
@@ -339,19 +340,22 @@ def _sort_result(self, result: Frame) -> Frame:
             if isinstance(result, cudf.Index):
                 sort_order = result._get_sorted_inds()
             else:
-                sort_order = result._get_sorted_inds(_coerce_to_list(self.on))
+                # need a list instead of a tuple here because
+                # _get_sorted_inds calls down to ColumnAccessor.get_by_label
+                # which handles lists and tuples differently
+                sort_order = result._get_sorted_inds(list(self.on))
             return result._gather(sort_order, keep_index=False)
         by = []
         if self.left_index and self.right_index:
             if result._index is not None:
                 by.extend(result._index._data.columns)
         if self.left_on:
             by.extend(
-                [result._data[col] for col in _coerce_to_list(self.left_on)]
+                [result._data[col] for col in _coerce_to_tuple(self.left_on)]
             )
         if self.right_on:
             by.extend(
-                [result._data[col] for col in _coerce_to_list(self.right_on)]
+                [result._data[col] for col in _coerce_to_tuple(self.right_on)]
             )
         if by:
             to_sort = cudf.DataFrame._from_columns(by)