feat: add renameOperator (#19776)

(cherry picked from commit 3c28cd4625)

superset/utils/pandas_postprocessing/__init__.py

@@ -28,6 +28,7 @@ from superset.utils.pandas_postprocessing.geography import (
 )
 from superset.utils.pandas_postprocessing.pivot import pivot
 from superset.utils.pandas_postprocessing.prophet import prophet
+from superset.utils.pandas_postprocessing.rename import rename
 from superset.utils.pandas_postprocessing.resample import resample
 from superset.utils.pandas_postprocessing.rolling import rolling
 from superset.utils.pandas_postprocessing.select import select
@@ -46,6 +47,7 @@ __all__ = [
     "geodetic_parse",
     "pivot",
     "prophet",
+    "rename",
     "resample",
     "rolling",
     "select",

superset/utils/pandas_postprocessing/flatten.py

@@ -81,14 +81,16 @@ def flatten(
     """
     if _is_multi_index_on_columns(df):
         df.columns = df.columns.droplevel(drop_levels)
-        # every cell should be converted to string
-        df.columns = [
-            FLAT_COLUMN_SEPARATOR.join(
-                # pylint: disable=superfluous-parens
-                [str(cell) for cell in (series if is_sequence(series) else [series])]
-            )
-            for series in df.columns.to_flat_index()
-        ]
+        _columns = []
+        for series in df.columns.to_flat_index():
+            _cells = []
+            for cell in series if is_sequence(series) else [series]:
+                if pd.notnull(cell):
+                    # every cell should be converted to string
+                    _cells.append(str(cell))
+            _columns.append(FLAT_COLUMN_SEPARATOR.join(_cells))
+
+        df.columns = _columns
 
     if reset_index and not isinstance(df.index, pd.RangeIndex):
         df = df.reset_index(level=0)

superset/utils/pandas_postprocessing/rename.py

@@ -0,0 +1,58 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+from typing import Dict, Optional, Union
+
+import pandas as pd
+from flask_babel import gettext as _
+from pandas._typing import Level
+
+from superset.exceptions import InvalidPostProcessingError
+from superset.utils.pandas_postprocessing.utils import validate_column_args
+
+
+@validate_column_args("columns")
+def rename(
+    df: pd.DataFrame,
+    columns: Dict[str, Union[str, None]],
+    inplace: bool = False,
+    level: Optional[Level] = None,
+) -> pd.DataFrame:
+    """
+    Alter column name of DataFrame
+
+    :param df: DataFrame to rename.
+    :param columns: The offset string representing target conversion.
+    :param inplace: Whether to return a new DataFrame.
+    :param level: In case of a MultiIndex, only rename labels in the specified level.
+    :return: DataFrame after rename
+    :raises InvalidPostProcessingError: If the request is unexpected
+    """
+    if not columns:
+        return df
+
+    try:
+        _rename_level = df.columns.get_level_values(level=level)
+    except (IndexError, KeyError) as err:
+        raise InvalidPostProcessingError from err
+
+    if all(new_name in _rename_level for new_name in columns.values()):
+        raise InvalidPostProcessingError(_("Label already exists"))
+
+    if inplace:
+        df.rename(columns=columns, inplace=inplace, level=level)
+        return df
+    return df.rename(columns=columns, inplace=inplace, level=level)