def _make_final_rowindex(self) -> Optional[core.RowIndex]:
"""
Construct the "final" RowIndex object.
If the source Frame is a view, then the returned RowIndex is an
uplifted version of the "source" RowIndex. Otherwise the final RowIndex
is the same object as the source RowIndex. The returned value may also
be None indicating absense of any RowIndex.
"""
_dt = self._engine.dt.internal
ri_source = self._make_source_rowindex()
ri_target = _dt.rowindex
if self._inverse:
if ri_source is None:
return core.rowindex_from_slice(0, 0, 0)
elif ri_target is None:
return ri_source.inverse(_dt.nrows)
else:
return ri_source.inverse(_dt.nrows).uplift(ri_target)
if ri_source is None:
return ri_target
else:
if ri_target is None:
return ri_source
else:
return ri_source.uplift(ri_target)
def _make_source_rowindex(self):
return core.rowindex_from_slice(*self._triple)