如何在python中订购字典列表

Question

I have list of dictionaries as follows:

[
  {'id': 16419, 'name': 'Audi'},
  {'id': 13, 'name': 'BMW'},
  {'id': 31, 'name': 'Honda'},
  {'id': 50060, 'name': 'KTM'},
  {'id': 54, 'name': 'Opel'},
  {'id': 55, 'name': 'Peugeot'},
  {'id': 50083, 'name': 'PGO'},
  {'id': 16350, 'name': 'Skoda'},
  {'id': 68, 'name': 'Suzuki'},
  {'id': 2120, 'name': 'Triumph'},
  {'id': 16328, 'name': 'Others'},
  {'id': 16396, 'name': 'Seat'},
  {'id': 14979, 'name': 'Opel'},
  {'id': 6, 'name': 'Volkswagen'}
]

What I want to do is to order it. And I want that some dictionaries with some name values show in the beginning of the list.

I want that for example Volkswagen , Audi , BMW , Opel , Peugeot as first params appears in list.

Thus the wanted result should be something like this:

[
  {'id': 6, 'name': 'Volkswagen'}
  {'id': 16419, 'name': 'Audi'},
  {'id': 13, 'name': 'BMW'},
  {'id': 54, 'name': 'Opel'},
  {'id': 55, 'name': 'Peugeot'},
  {'id': 31, 'name': 'Honda'},
  {'id': 50060, 'name': 'KTM'},
  {'id': 50083, 'name': 'PGO'},
  {'id': 16350, 'name': 'Skoda'},
  {'id': 68, 'name': 'Suzuki'},
  {'id': 2120, 'name': 'Triumph'},
  {'id': 16328, 'name': 'Others'},
  {'id': 16396, 'name': 'Seat'},
  {'id': 14979, 'name': 'Opel'},
]

Any idea how to do that?

Answer 1

You can use an appropriate key function for your sorting. This one orders by the given names first (in the given order). All other brands come after that with no order specified among themselves:

>>> rank = {x: i for i, x in enumerate(['Volkswagen', 'Audi', 'BMW', 'Opel', 'Peugeot'])}
# {'Volkswagen': 0, 'Audi': 1, ...}
>>> sorted(lst, key=lambda x: rank.get(x['name'], len(rank)))
[{'id': 6, 'name': 'Volkswagen'},
 {'id': 16419, 'name': 'Audi'},
 {'id': 13, 'name': 'BMW'},
 {'id': 54, 'name': 'Opel'},
 {'id': 14979, 'name': 'Opel'},
 {'id': 55, 'name': 'Peugeot'},
 {'id': 31, 'name': 'Honda'},
 {'id': 50060, 'name': 'KTM'},
 {'id': 50083, 'name': 'PGO'},
 {'id': 16350, 'name': 'Skoda'},
 {'id': 68, 'name': 'Suzuki'},
 {'id': 2120, 'name': 'Triumph'},
 {'id': 16328, 'name': 'Others'},
 {'id': 16396, 'name': 'Seat'}]

Answer 2

You can use a dictionary to define a custom sorting order.

dicts = [
  {'id': 16419, 'name': 'Audi'},
  {'id': 13, 'name': 'BMW'},
  {'id': 31, 'name': 'Honda'},
  {'id': 50060, 'name': 'KTM'},
  {'id': 54, 'name': 'Opel'},
  {'id': 55, 'name': 'Peugeot'},
  {'id': 50083, 'name': 'PGO'},
  {'id': 16350, 'name': 'Skoda'},
  {'id': 68, 'name': 'Suzuki'},
  {'id': 2120, 'name': 'Triumph'},
  {'id': 16328, 'name': 'Others'},
  {'id': 16396, 'name': 'Seat'},
  {'id': 14979, 'name': 'Opel'},
  {'id': 6, 'name': 'Volkswagen'}
]

brand_order = ['Volkswagen', 'Audi', 'BMW', 'Opel', 'Peugeot']
order = dict(zip(brand_order, range(len(brand_order))))

dicts_sorted = sorted(dicts, key=lambda d: order.get(d['name'], float('inf')))
print(dicts_sorted)

Output:

[{'id': 6, 'name': 'Volkswagen'}, 
 {'id': 16419, 'name': 'Audi'}, 
 {'id': 13, 'name': 'BMW'},
 {'id': 54, 'name': 'Opel'},
 {'id': 14979, 'name': 'Opel'},
 {'id': 55, 'name': 'Peugeot'},
 {'id': 31, 'name': 'Honda'},
 {'id': 50060, 'name': 'KTM'},
 {'id': 50083, 'name': 'PGO'},
 {'id': 16350, 'name': 'Skoda'},
 {'id': 68, 'name': 'Suzuki'},
 {'id': 2120, 'name': 'Triumph'},
 {'id': 16328, 'name': 'Others'},
 {'id': 16396, 'name': 'Seat'}]

Falling back to float('inf') ensures that whatever is not in order comes last.