FEAT-#2363: introduce getter and setter for index name (#2368)

Signed-off-by: ienkovich <ilya.enkovich@intel.com>

modin/backends/base/query_compiler.py

@@ -1584,6 +1584,50 @@ def has_multiindex(self, axis=0):
         assert axis == 1
         return isinstance(self.columns, pandas.MultiIndex)
 
+    def get_index_name(self):
+        """
+        Get index name.
+
+        Returns
+        -------
+        hashable
+            Index name, None for MultiIndex.
+        """
+        return self.index.name
+
+    def set_index_name(self, name):
+        """
+        Set index name.
+
+        Parameters
+        ----------
+        name: hashable
+            New index name.
+        """
+        self.index.name = name
+
+    def get_index_names(self):
+        """
+        Get index names.
+
+        Returns
+        -------
+        list
+            Index names.
+        """
+        return self.index.names
+
+    def set_index_names(self, names):
+        """
+        Set index names.
+
+        Parameters
+        ----------
+        names: list
+            New index names.
+        """
+        self.index.names = names
+
     # DateTime methods
 
     dt_ceil = DateTimeDefault.register(pandas.Series.dt.ceil)

modin/experimental/backends/omnisci/query_compiler.py

@@ -646,6 +646,18 @@ def has_multiindex(self, axis=0):
         assert axis == 1
         return isinstance(self.columns, pandas.MultiIndex)
 
+    def get_index_name(self):
+        return self._modin_frame.get_index_name()
+
+    def set_index_name(self, name):
+        self._modin_frame = self._modin_frame.set_index_name(name)
+
+    def get_index_names(self):
+        return self._modin_frame.get_index_names()
+
+    def set_index_names(self, names):
+        self._modin_frame = self._modin_frame.set_index_names(names)
+
     def free(self):
         return
 

modin/experimental/engines/omnisci_on_ray/frame/data.py

@@ -1235,6 +1235,69 @@ def has_multiindex(self):
             return isinstance(self._index_cache, MultiIndex)
         return self._index_cols is not None and len(self._index_cols) > 1
 
+    def get_index_name(self):
+        if self._index_cols is None:
+            return None
+        if len(self._index_cols) > 1:
+            return None
+        return self._index_cols[0]
+
+    def set_index_name(self, name):
+        if self.has_multiindex():
+            ErrorMessage.single_warning("Scalar name for MultiIndex is not supported!")
+            return self
+
+        if self._index_cols is None and name is None:
+            return self
+
+        names = self._mangle_index_names([name])
+        if self._index_cols is None:
+            exprs = OrderedDict()
+            exprs[name] = self.ref("__rowid__")
+        else:
+            exprs = self._index_exprs()
+
+        for col in self.columns:
+            exprs[col] = self.ref(col)
+
+        return self.__constructor__(
+            columns=self.columns,
+            dtypes=self._dtypes_for_exprs(exprs),
+            op=TransformNode(self, exprs),
+            index_cols=names,
+            uses_rowid=self._index_cols is None,
+            force_execution_mode=self._force_execution_mode,
+        )
+
+    def get_index_names(self):
+        if self.has_multiindex():
+            return self._index_cols.copy()
+        return [self.get_index_name()]
+
+    def set_index_names(self, names):
+        if not self.has_multiindex():
+            raise ValueError("Can set names for MultiIndex only")
+
+        if len(names) != len(self._index_cols):
+            raise ValueError(
+                f"Unexpected names count: expected {len(self._index_cols)} got {len(names)}"
+            )
+
+        names = self._mangle_index_names(names)
+        exprs = OrderedDict()
+        for old, new in zip(self._index_cols, names):
+            exprs[new] = self.ref(old)
+        for col in self.columns:
+            exprs[col] = self.ref(col)
+
+        return self.__constructor__(
+            columns=self.columns,
+            dtypes=self._dtypes_for_exprs(exprs),
+            op=TransformNode(self, exprs),
+            index_cols=names,
+            force_execution_mode=self._force_execution_mode,
+        )
+
     def to_pandas(self):
         self._execute()
 

modin/experimental/engines/omnisci_on_ray/test/test_dataframe.py

@@ -392,6 +392,30 @@ def applier(lib):
 
         eval_general(pd, pandas, applier)
 
+    def test_set_index_name(self):
+        index = pandas.Index.__new__(pandas.Index, data=[i for i in range(24)])
+
+        pandas_df = pandas.DataFrame(self.data, index=index)
+        pandas_df.index.name = "new_name"
+        modin_df = pd.DataFrame(self.data, index=index)
+        modin_df._query_compiler.set_index_name("new_name")
+
+        df_equals(pandas_df, modin_df)
+
+    def test_set_index_names(self):
+        index = pandas.MultiIndex.from_tuples(
+            [(i, j, k) for i in range(2) for j in range(3) for k in range(4)]
+        )
+
+        pandas_df = pandas.DataFrame(self.data, index=index)
+        pandas_df.index.names = ["new_name1", "new_name2", "new_name3"]
+        modin_df = pd.DataFrame(self.data, index=index)
+        modin_df._query_compiler.set_index_names(
+            ["new_name1", "new_name2", "new_name3"]
+        )
+
+        df_equals(pandas_df, modin_df)
+
 
 class TestFillna:
     data = {"a": [1, 1, None], "b": [None, None, 2], "c": [3, None, None]}

modin/pandas/groupby.py

@@ -909,10 +909,10 @@ def _apply_agg_function(self, f, drop=True, *args, **kwargs):
             drop=self._drop,
         )
         if self._idx_name is not None and self._as_index:
-            new_manager.index.name = self._idx_name
+            new_manager.set_index_name(self._idx_name)
         result = type(self._df)(query_compiler=new_manager)
-        if result.index.name == "__reduced__":
-            result.index.name = None
+        if result._query_compiler.get_index_name() == "__reduced__":
+            result._query_compiler.set_index_name(None)
         if self._kwargs.get("squeeze", False):
             return result.squeeze()
         return result