Sorting list of lists by a third list of specified non-sorted order

Question

I have a list:

[[\'18411971\', \'kinase_2\', 36], [\'75910712\', \'unnamed...\', 160], ...

• about 60 entries long
• each entry

Answer 1

The usual idiom is to sort using a key:

>>> a = [[1,2],[2,10,10],[3,4,'fred']]
>>> b = [2,1,3]
>>> sorted(a,key=lambda x: b.index(x[0]))
[[2, 10, 10], [1, 2], [3, 4, 'fred']]

This can have performance issues, though-- if the keys are hashable, this will probably be faster for long lists:

>>> order_dict = dict(zip(b, range(len(b))))
>>> sorted(a,key=lambda x: order_dict[x[0]])
[[2, 10, 10], [1, 2], [3, 4, 'fred']]