在python中按日期排序字典值列表

Question

我有一个列表,当我循环访问我的数据时,我正在附加一个字典...我希望按其中一个字典键排序.

例如:

data = "data from database"
list = []
for x in data:
     dict = {'title':title, 'date': x.created_on}
     list.append(dict)

我想按"date"的值按相反的顺序对列表进行排序

Answer 1

你可以这样做:

list.sort(key=lambda item:item['date'], reverse=True)

Answer 2

from operator import itemgetter

your_list.sort(key=itemgetter('date'), reverse=True)

相关说明

• 不要使用list,dict作为变量名,它们是Python中的内置名称.它使您的代码难以阅读.

• 您可能需要根据上下文替换字典tuple或者使用collections.namedtuple类似自定义类的类替换字典

  from collections import namedtuple
  from operator    import itemgetter
  
  Row = namedtuple('Row', 'title date')
  rows = [Row(row.title, row.created_on) for row in data]
  rows.sort(key=itemgetter(1), reverse=True)
  

例:

>>> lst = [Row('a', 1), Row('b', 2)]
>>> lst.sort(key=itemgetter(1), reverse=True)
>>> lst
[Row(title='b', date=2), Row(title='a', date=1)]

要么

>>> from operator import attrgetter
>>> lst = [Row('a', 1), Row('b', 2)]
>>> lst.sort(key=attrgetter('date'), reverse=True)
>>> lst
[Row(title='b', date=2), Row(title='a', date=1)]

下面是如何namedtuple看起来里面:

>>> Row = namedtuple('Row', 'title date', verbose=True)

class Row(tuple):
        'Row(title, date)'

        __slots__ = ()

        _fields = ('title', 'date')

        def __new__(cls, title, date):
            return tuple.__new__(cls, (title, date))

        @classmethod
        def _make(cls, iterable, new=tuple.__new__, len=len):
            'Make a new Row object from a sequence or iterable'
            result = new(cls, iterable)
            if len(result) != 2:
                raise TypeError('Expected 2 arguments, got %d' % len(result))
            return result

        def __repr__(self):
            return 'Row(title=%r, date=%r)' % self

        def _asdict(t):
            'Return a new dict which maps field names to their values'
            return {'title': t[0], 'date': t[1]}

        def _replace(self, **kwds):
            'Return a new Row object replacing specified fields with new values'

            result = self._make(map(kwds.pop, ('title', 'date'), self))
            if kwds:
                raise ValueError('Got unexpected field names: %r' % kwds.keys())

            return result

        def __getnewargs__(self):
            return tuple(self)

        title = property(itemgetter(0))
        date = property(itemgetter(1))