Merge pull request #11921 from taldcroft/table-pandas-1.3-index-name

taldcroft · eteq · commit 4e58cf4fcbec · 2021-07-23T15:59:50.000-04:00
Fix problem in to_pandas() introduced in pandas 1.3.0
diff --git a/astropy/table/table.py b/astropy/table/table.py
@@ -3682,7 +3682,13 @@ def _encode_mixins(tbl):
                 if isinstance(v, Series):
                     v.index = idx
 
-        return DataFrame(out, **kwargs)
+        df = DataFrame(out, **kwargs)
+        if index:
+            # Explicitly set the pandas DataFrame index to the original table
+            # index name.
+            df.index.name = idx.info.name
+
+        return df
 
     @classmethod
     def from_pandas(cls, dataframe, index=False, units=None):
diff --git a/docs/changes/table/11921.bugfix.rst b/docs/changes/table/11921.bugfix.rst
@@ -0,0 +1,5 @@
+Fix an issue in ``Table.to_pandas(index=<colname>)`` where the index column name
+was not being set properly for the ``DataFrame`` index. This was introduced by
+an API change in pandas version 1.3.0. Previously when creating a ``DataFrame``
+with the index set to an astropy ``Column``, the ``DataFrame`` index name was
+automatically set to the column name.
