Would it be something as simple as: rows.sort(key = lambda x: (x[0], x[3], x[4], sort_list.index(x[6])))
-----Original Message----- From: Python-list <python-list-bounces+david.raymond=tomtom....@python.org> On Behalf Of Larry Martell Sent: Wednesday, September 2, 2020 1:55 PM To: Python <python-list@python.org> Subject: grouping and sorting within groups using another list I have a list of tuples, and I want to group them by 3 items (0, 3, 4) and then within each group sort the data by a 4th item (6) using a sort order from another list. The list is always ordered by the 3 grouping items. For example, if I have this list: rows = [('a', 'b', 'c', 'd', 'e', 'f', 'blue', ....), ('a', 'x', 'y', 'd', 'e', 'f', 'green', ....), ('a', 'q', 'w', 'd', 'e', 'f', 'white', ....), ('p', 'x', 'y', 'd', 'e', 'f', 'white', ....), ('p', 'x', 'y', 'd', 'e', 'f', ' 'blue', ...), ('p', 'x', 'y', 'd', 'e', 'f', ' 'green', ...), ('z', 'x', 'y', 'm', 'n', 'o', 'green, ...), ('z', 'x', 'y', 'm', 'n', 'o', 'white, ...), ('z', 'x', 'y', 'm', 'n', 'o', 'blue, ...), ] and I have a list: sort_list = ['blue', 'white', 'green'] Then the result list would be: [('a', 'b', 'c', 'd', 'e', 'f', 'blue', ....), ('a', 'x', 'y', 'd', 'e', 'f', 'white', ....), ('a', 'q', 'w', 'd', 'e', 'f', 'green', ....), ('p', 'x', 'y', 'd', 'e', 'f', 'blue', ....), ('p', 'x', 'y', 'd', 'e', 'f', ' 'white', ...), ('p', 'x', 'y', 'd', 'e', 'f', ' 'green', ...), ('z', 'x', 'y', 'm', 'n', 'o', 'blue, ...), ('z', 'x', 'y', 'm', 'n', 'o', 'white, ...), ('z', 'x', 'y', 'm', 'n', 'o', 'green, ...), ] Been trying to do with using groupby but have not been successful. -- https://mail.python.org/mailman/listinfo/python-list -- https://mail.python.org/mailman/listinfo/python-list