Python 如何在datetime上对类进行排序，对集合进行排序.deque

在如何实现getitem、iter方法或生成器函数对我创建的类和类容器进行排序方面，我确实需要一些帮助

我创建了一个具有send_time（datetime）和period_length（int）属性的报表类。 我还为报表创建了一个ReportDeque容器，它继承自collections.deque

我需要向类及其容器添加排序功能

到目前为止，我已经对工作进行了排序，但希望得到list.sort（）样式的工作

  sortedList = sorted(list, key=lambda report: report.send_time)
  sortedDeque = sorted(deque, key=lambda report: report.send_time)

我正在努力实现Report中的getitem，以及ReportDeque中的iter，next方法。我只是找不到我需要的例子来让这一切正常运作

也许应该使用生成器函数对collections.deque容器进行排序。 如果有多种生成器以不同的方式对deque进行排序，那就太好了

下面是我的测试用例。要在以下代码中运行unittest，请键入：

  python -m unittest test_reports

输出在这篇文章的末尾

先谢谢你

-------------------test_reports.py snip--------------------------

#!/usr/bin/env python

from datetime import datetime
from collections import deque
import unittest
import inspect

class Report(object):
    """
    Contains all information contained in a report
    """
    def __init__(self, periodStart, periodEnd, sendTime):
        self.period_start = periodStart
        self.period_end = periodEnd
        self.send_time = sendTime
        self.send_timestamp = (sendTime - datetime(1970, 1, 1)).total_seconds()
        self.period_length = (periodEnd - periodStart).total_seconds()

    #def __getitem__(self, key):

class ReportDeque(deque):
    """
    Container for processing, sorting Report objects
    """

    #def __iter__(self)

    #def next(self)

class TestReports(unittest.TestCase):

    def setUp(self):

        self.list = []
        self.deque = ReportDeque()

        # send_time 12/4/13, day length report
        report = Report(datetime(2013, 12, 3, 0), datetime(2013, 12, 3, 23), datetime(2013, 12, 4, 0))
        self.list.append(report)
        self.deque.append(report)
        # send_time 12/3/13, day length report
        report = Report(datetime(2013, 12, 2, 0), datetime(2013, 12, 2, 23), datetime(2013, 12, 3, 0))
        self.list.append(report)
        self.deque.append(report)
        # send_time 12/2/13, day length report
        report = Report(datetime(2013, 12, 1, 0), datetime(2013, 12, 1, 23), datetime(2013, 12, 2, 0))
        self.list.append(report)
        self.deque.append(report)

        # sorted with key function works
        self.sortedList = sorted(self.list, key=lambda report: report.send_time)
        self.sortedDeque = sorted(self.deque, key=lambda report: report.send_time)

    def test_sort_deque_send_time(self):
        self.print_inspect()
        # deque does not have sort method. How to sort it?
        self.deque.sort()
        firstReport = self.deque[0]
        print "send_time {} period_length {}".format(firstReport.send_time, firstReport.period_length)
        self.assertEqual(firstReport.send_time, datetime(2013, 12, 2, 0, 0, 0, 0))

    def test_sort_list_send_time(self):
        self.print_inspect()
        # list.sort() not working. How to implement __get_item___?
        self.list.sort()
        firstReport = self.list[0]
        print "send_time {} period_length {}".format(firstReport.send_time, firstReport.period_length)
        self.assertEqual(firstReport.send_time, datetime(2013, 12, 2, 0, 0, 0, 0))

    def test_sorted_deque_send_time(self):
        self.print_inspect()
        firstReport = self.sortedDeque[0]
        print "send_time {} period_length {}".format(firstReport.send_time, firstReport.period_length)
        self.assertEqual(firstReport.send_time, datetime(2013, 12, 2, 0, 0, 0, 0))

    def test_sorted_list_send_time(self):
        self.print_inspect()
        firstReport = self.sortedList[0]
        print "send_time {} period_length {}".format(firstReport.send_time, firstReport.period_length)
        self.assertEqual(firstReport.send_time, datetime(2013, 12, 2, 0, 0, 0, 0))

    def print_inspect(self):
        calling_function = inspect.stack()[1][3]
        print "\nin {}()".format(calling_function)


if __name__ == "__main__":
    unittest.main()

    $ python -m unittest test_reports


    in test_sort_deque_send_time()
    E
    in test_sort_list_send_time()
    send_time 2013-12-04 00:00:00 period_length 82800.0
    F
    in test_sorted_deque_send_time()
    send_time 2013-12-02 00:00:00 period_length 82800.0
    .
    in test_sorted_list_send_time()
    send_time 2013-12-02 00:00:00 period_length 82800.0
    .
    ======================================================================
    ERROR: test_sort_deque_send_time (test_reports.TestReports)
    ----------------------------------------------------------------------
    Traceback (most recent call last):
      File "test_reports.py", line 51, in test_sort_deque_send_time
        self.deque.sort()
    AttributeError: 'ReportsDeque' object has no attribute 'sort'

    ======================================================================
    FAIL: test_sort_list_send_time (test_reports.TestReports)
    ----------------------------------------------------------------------
    Traceback (most recent call last):
      File "test_reports.py", line 62, in test_sort_list_send_time
        self.assertEqual(firstReport.send_time, datetime(2013, 12, 2, 0, 0, 0, 0))
    AssertionError: datetime.datetime(2013, 12, 4, 0, 0) != datetime.datetime(2013, 12, 2, 0, 0)

----------------------------------------------------------------------
Ran 4 tests in 0.011s

FAILED (failures=1, errors=1)

-------------------test_reports.py snip--------------------------

#!/usr/bin/env python

from datetime import datetime
from collections import deque
import unittest
import inspect

class Report(object):
    """
    Contains all information contained in a report
    """
    def __init__(self, periodStart, periodEnd, sendTime):
        self.period_start = periodStart
        self.period_end = periodEnd
        self.send_time = sendTime
        self.send_timestamp = (sendTime - datetime(1970, 1, 1)).total_seconds()
        self.period_length = (periodEnd - periodStart).total_seconds()

    #def __getitem__(self, key):

class ReportDeque(deque):
    """
    Container for processing, sorting Report objects
    """

    #def __iter__(self)

    #def next(self)

class TestReports(unittest.TestCase):

    def setUp(self):

        self.list = []
        self.deque = ReportDeque()

        # send_time 12/4/13, day length report
        report = Report(datetime(2013, 12, 3, 0), datetime(2013, 12, 3, 23), datetime(2013, 12, 4, 0))
        self.list.append(report)
        self.deque.append(report)
        # send_time 12/3/13, day length report
        report = Report(datetime(2013, 12, 2, 0), datetime(2013, 12, 2, 23), datetime(2013, 12, 3, 0))
        self.list.append(report)
        self.deque.append(report)
        # send_time 12/2/13, day length report
        report = Report(datetime(2013, 12, 1, 0), datetime(2013, 12, 1, 23), datetime(2013, 12, 2, 0))
        self.list.append(report)
        self.deque.append(report)

        # sorted with key function works
        self.sortedList = sorted(self.list, key=lambda report: report.send_time)
        self.sortedDeque = sorted(self.deque, key=lambda report: report.send_time)

    def test_sort_deque_send_time(self):
        self.print_inspect()
        # deque does not have sort method. How to sort it?
        self.deque.sort()
        firstReport = self.deque[0]
        print "send_time {} period_length {}".format(firstReport.send_time, firstReport.period_length)
        self.assertEqual(firstReport.send_time, datetime(2013, 12, 2, 0, 0, 0, 0))

    def test_sort_list_send_time(self):
        self.print_inspect()
        # list.sort() not working. How to implement __get_item___?
        self.list.sort()
        firstReport = self.list[0]
        print "send_time {} period_length {}".format(firstReport.send_time, firstReport.period_length)
        self.assertEqual(firstReport.send_time, datetime(2013, 12, 2, 0, 0, 0, 0))

    def test_sorted_deque_send_time(self):
        self.print_inspect()
        firstReport = self.sortedDeque[0]
        print "send_time {} period_length {}".format(firstReport.send_time, firstReport.period_length)
        self.assertEqual(firstReport.send_time, datetime(2013, 12, 2, 0, 0, 0, 0))

    def test_sorted_list_send_time(self):
        self.print_inspect()
        firstReport = self.sortedList[0]
        print "send_time {} period_length {}".format(firstReport.send_time, firstReport.period_length)
        self.assertEqual(firstReport.send_time, datetime(2013, 12, 2, 0, 0, 0, 0))

    def print_inspect(self):
        calling_function = inspect.stack()[1][3]
        print "\nin {}()".format(calling_function)


if __name__ == "__main__":
    unittest.main()

    $ python -m unittest test_reports


    in test_sort_deque_send_time()
    E
    in test_sort_list_send_time()
    send_time 2013-12-04 00:00:00 period_length 82800.0
    F
    in test_sorted_deque_send_time()
    send_time 2013-12-02 00:00:00 period_length 82800.0
    .
    in test_sorted_list_send_time()
    send_time 2013-12-02 00:00:00 period_length 82800.0
    .
    ======================================================================
    ERROR: test_sort_deque_send_time (test_reports.TestReports)
    ----------------------------------------------------------------------
    Traceback (most recent call last):
      File "test_reports.py", line 51, in test_sort_deque_send_time
        self.deque.sort()
    AttributeError: 'ReportsDeque' object has no attribute 'sort'

    ======================================================================
    FAIL: test_sort_list_send_time (test_reports.TestReports)
    ----------------------------------------------------------------------
    Traceback (most recent call last):
      File "test_reports.py", line 62, in test_sort_list_send_time
        self.assertEqual(firstReport.send_time, datetime(2013, 12, 2, 0, 0, 0, 0))
    AssertionError: datetime.datetime(2013, 12, 4, 0, 0) != datetime.datetime(2013, 12, 2, 0, 0)

----------------------------------------------------------------------
Ran 4 tests in 0.011s

FAILED (failures=1, errors=1)

---

首先，您需要使报表对象具有可比性，以便无需显式键即可排序。您可能应该仔细阅读丰富的比较，但是

\uu\cmp\uuu

可以做到这一点

class Report(object):
    """
    Contains all information contained in a report
    """
    def __init__(self, periodStart, periodEnd, sendTime):
        self.period_start = periodStart
        self.period_end = periodEnd
        self.send_time = sendTime
        self.send_timestamp = (sendTime - datetime(1970, 1, 1)).total_seconds()
        self.period_length = (periodEnd - periodStart).total_seconds()

    def __cmp__(self, other):
        return cmp(self.send_time, other.send_time)

在测试

list.sort（）

时，这就是让测试通过所需的全部内容。对

sorted（list）

和

sorted（deque）

的测试也应该有效，但有一个问题。由于您正在请求有关

\uu getitem\uuu

实现的帮助，我认为您认为

sorted（）

正在进行排序，并且也会对您的数据进行排序。这不是它的工作原理

sorted（iterable）

将返回一个包含iterable项的新排序列表

如果你真的想在适当的位置对数据进行排序，你必须在

deque.sort（）

方法中实现一个deque排序算法才能在适当的位置进行排序，我不知道哪种算法对数据进行排序更有效（我甚至不确定这样做是否有意义），但我认为重建deque并利用python非常高效的排序算法可能更容易：

class ReportDeque(deque):
    """
    Container for processing, sorting Report objects
    """

    def sort(self, *args, **kwargs):        
        items = [self.pop() for x in xrange(len(self))]
        items.sort(*args, **kwargs)
        self.extend(items)

这会让你所有的考试都通过

更新

如果您希望在发送时间相等时使用

周期长度

来消除歧义，只需将其添加到

\uuuuuu cmp\uuuu

，如下所示：

    def __cmp__(self, other):
         cmp((self.send_time, self.period_length), 
             (other.send_time, other.period_length))

---

它是

ReportsDeque

还是

ReportDeque

？我最初将报告集合命名为ReportsDeque（复数），但不断错误地反复输入ReportDeque（单数），因此在代码示例中我将其重命名为ReportDeque（singlular）。有语法错误吗？复数可能是一个更好的名称。强制代码golf:

def sort（self，*args，**kwargs）：self.extend（sorted（self.pop（）表示x范围内的x（len（self）），*args，**kwargs））

。这是我的第一次实施。：）谢谢你，佩德罗和金达尔。刚吃过午饭回来，我就要开始工作了。定义cmp是有意义的。我盯着getitem和iter想“见鬼！”我知道sorted（）返回list，这段代码很好地工作

sorteddque=sorted（deque，key=lambda report:report.send_time）

可能是对deque的有效排序。deque.sort（）算法的答案非常受欢迎，因为我最终希望实现ReportDeque sort（），并在第一次发送时间（从最早到最新），然后（当发送时间相等时）周期长度（从最小到最大）上进行排序。@Bradsurtevant使用

\uu cmp\uuuuuu

，sorted（deque）也可以工作，没有关键参数。您提到的辅助排序条件也是

\uuuu cmp\uuu

的一部分，它与deque.sort（）无关。我将编辑答案以添加该选项。我真的怀疑任何可以实现的deque sort（）算法是否会比python的内置list.sort（）更好，即使是以重建deque为代价。@Pedro再次感谢您，“检查”了您的答案