add get_row_key to DataTable

CHANGELOG.md

@@ -26,6 +26,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Added `DOMNode.displayed_children` https://github.com/Textualize/textual/pull/6070
 - Added `TextArea.UserInsert` message https://github.com/Textualize/textual/pull/6070
 - Added `TextArea.hide_suggestion_on_blur` boolean https://github.com/Textualize/textual/pull/6070
+- Added `DataTable.get_row_key` https://github.com/Textualize/textual/pull/6081
 
 ### Changed
 

src/textual/widgets/_data_table.py

@@ -1033,6 +1033,22 @@ def get_row_index(self, row_key: RowKey | str) -> int:
             raise RowDoesNotExist(f"No row exists for row_key={row_key!r}")
         return self._row_locations.get(row_key)
 
+    def get_row_key(self, row_index: int) -> RowKey:
+        """Return the current key for the row identified by row_index.
+
+        Args:
+            row_index: The index of the row.
+
+        Returns:
+            The current key of the specified row index.
+
+        Raises:
+            RowDoesNotExist: If there is no row with the given index.
+        """
+        if not self.is_valid_row_index(row_index):
+            raise RowDoesNotExist(f"Row index {row_index!r} is not valid.")
+        return self._row_locations.get_key(row_index)
+
     def get_column(self, column_key: ColumnKey | str) -> Iterable[CellType]:
         """Get the values from the column identified by the given column key.