在python中对嵌套列表进行排序会导致TypeError

Question

I have below nested list (lists of list) called row_list :

[
    [
        {
            'text': 'Something',
            'x0': Decimal('223.560')
        },
        {
            'text': 'else',
            'x0': Decimal('350')
        },
        {
            'text': 'should',
            'x0': Decimal('373.736')
        },
        {
            'text': 'be',
            'x0': Decimal('21.600')
        }
    ],
    [
        {
            'text': 'here',
            'x0': Decimal('21.600')
        }
    ]
]

I am trying to sort all inner list by the x0 key:

row_list = sorted(row_list, key=lambda x:x['x0'])

However, above gives me the error:

TypeError: list indices must be integers or slices, not str

I've tried using itemgetter as well:

row_list = sorted(row_list, key=itemgetter('x0'))

But that gives me the same error.

What am I doing wrong?

Answer 1

you have a nested list. if you want to create a new list:

row_list = [list(sorted(item, key=lambda x: x["x0"])) for item in row_list]

which produces

[[{'text': 'be', 'x0': Decimal('21.600')},
  {'text': 'Something', 'x0': Decimal('223.560')},
  {'text': 'else', 'x0': Decimal('350')},
  {'text': 'should', 'x0': Decimal('373.736')}],
 [{'text': 'here', 'x0': Decimal('21.600')}]]

if you want to keep the original list you could also sort inline instead of creating a new list:

for sublist in row_list:
     sublist.sort(key=lambda x: x["x0"])

Answer 2

from decimal import Decimal
l = [
    [
        {
            'text': 'Something',
            'x0': Decimal('223.560')
        },
        {
            'text': 'else',
            'x0': Decimal('350')
        },
        {
            'text': 'should',
            'x0': Decimal('373.736')
        },
        {
            'text': 'be',
            'x0': Decimal('21.600')
        }
    ],
    [
        {
            'text': 'here',
            'x0': Decimal('21.600')
        }
    ]]

for i in l:
    i.sort(key=lambda x:x['x0'])

print(l)

output

    [[{'text': 'be', 'x0': Decimal('21.600')},
  {'text': 'Something', 'x0': Decimal('223.560')},
  {'text': 'else', 'x0': Decimal('350')},
  {'text': 'should', 'x0': Decimal('373.736')}],
 [{'text': 'here', 'x0': Decimal('21.600')}]]