How do I sort this list of tuples by both values?

Question

I have a list of tuples: [(2, Operation.SUBSTITUTED), (1, Operation.DELETED), (2, Operation.INSERTED)]

I would like to sort this list in 2 ways:

Answer 1

In this particular case, because the order of comparison can be easily inverted for integers, you can sort in one time using negative value for integer key & reverse:

lst = [(2, 'Operation.SUBSTITUTED'), (1, 'Operation.DELETED'), (2, 'Operation.INSERTED')]
res = sorted(lst, key=lambda x: (-x[0],x[1]), reverse=True)

result:

[(1, 'Operation.DELETED'), (2, 'Operation.SUBSTITUTED'), (2, 'Operation.INSERTED')]

negating the integer key cancels the "reverse" aspect, only kept for the second string criterion.

Answer 2

Another way using itemgetter from operator module:

from operator import itemgetter

lst = [(2, 'Operation.SUBSTITUTED'), (1, 'Operation.DELETED'), (2, 'Operation.INSERTED')]

inter = sorted(lst, key=itemgetter(1), reverse=True)
sorted_lst = sorted(inter, key=itemgetter(0))

print(sorted_lst)

# [(1, 'Operation.DELETED'), (2, 'Operation.SUBSTITUTED'), (2, 'Operation.INSERTED')]                                

Answer 3

Since sorting is guaranteed to be stable, you can do this in 2 steps:

lst = [(2, 'Operation.SUBSTITUTED'), (1, 'Operation.DELETED'), (2, 'Operation.INSERTED')]

res_int = sorted(lst, key=lambda x: x[1], reverse=True)
res = sorted(res_int, key=lambda x: x[0])

print(res)

# [(1, 'Operation.DELETED'), (2, 'Operation.SUBSTITUTED'), (2, 'Operation.INSERTED')]

Answer 4

You can use this:

from operator import itemgetter
d = [(1, 'DELETED'), (2, 'INSERTED'), (2, 'SUBSTITUTED')]
d.sort(key=itemgetter(1),reverse=True)
d.sort(key=itemgetter(0))
print(d)