如何按递增顺序重新排列字典键(例如:一年中的日期作为键)?蟒蛇 3.

Question

我最近一直在使用字典，我正在做一个项目，其中包括将一天的事件保存到日历中。

因此，密钥的格式将采用日期格式 YYYY-MM-DD。我想这样做，以便字典中的每个"钥匙"都能按照日子出现。例如：键 2015-11-10 及其当天的事件和 2015-11-9 及其事件，我希望先打印出 2015-11-9 及其事件。我尝试过排序和元组等。但这只会对密钥内部的内容进行排序，而不是对密钥本身进行排序。有什么想法或建议吗？

>>> calendar = {}
    >>> command_add("2015-10-12", "Eye doctor", calendar)
    ''
    >>> command_add("2015-10-12", "lunch with sid", calendar)
    ''
    >>> command_add("2015-10-29", "Change oil in blue car", calendar)
    ''
    >>> command_add("2015-10-12", "dinner with Jane", calendar)
    ''
    >>> command_add("2015-10-29", "Fix tree near front walkway", calendar)
    ''
    >>> command_add("2015-10-29", "Get salad stuff", calendar)
    ''
    >>> command_add("2015-11-06", "Sid's birthday", calendar)
    ''
    >>> command_show(calendar)

我需要的是这个：

>>> command_show(calendar)
        2015-10-12:
            0: Eye doctor
            1: lunch with sid
            2: dinner with Jane
        2015-10-29:
            0: Change oil in blue car
            1: Fix tree near front walkway
            2: Get salad stuff
        2015-11-06:
            0: Sid's birthday
    ''

Answer 1

普通词典是无序的。如果你想要一个有序的字典，你必须使用OrderedDict .

但我想以有序的方式迭代值就足够了。通常，你这样做：

for key, value in sorted(mydict.items()):
    pass  # now it is sorted in ascending order of key

请注意，mydict仍然未订购。 .items()返回(key, value)元组的列表。并且可以对列表进行排序。

带有列表元素的字典

#!/usr/bin/env python

def command_add(day, event_name, calendar):
    if day in calendar:
        calendar[day].append(event_name)
    else:
        calendar[day] = [event_name]

def command_show(calendar):
    """
    Parameters
    ----------
    calendar : dict
        The keys are dates in the format YYYY-MM-DD and the values are lists
        of events
    """
    for day, events in sorted(calendar.items()):
        print("%s:" % day)
        for i, event in enumerate(events):
            print("t%i: %s" % (i, event))

calendar = {}
command_add("2015-10-12", "Eye doctor", calendar)
command_add("2015-10-12", "lunch with sid", calendar)
command_add("2015-10-29", "Change oil in blue car", calendar)
command_add("2015-10-12", "dinner with Jane", calendar)
command_add("2015-10-29", "Fix tree near front walkway", calendar)
command_add("2015-10-29", "Get salad stuff", calendar)
command_add("2015-11-06", "Sid's birthday", calendar)
command_show(calendar)