按值排序元组列表,然后按字母顺序排序

Question

有点蟒蛇新手,但我得到了以下的元组列表.我需要按值对其进行排序,如果值相同,则按字母顺序求解关系.这是一个示例:

#original
list_of_medals = [('Sweden', 24), ('Germany', 16), ('Russia', 10), ('Ireland', 10), ('Spain', 9), ('Albania', 8), ('Lithuania', 7), ('Iceland', 6), ('Malta', 5), ('Italy', 5), ('Serbia', 4), ('Estonia', 4), ('Turkey', 4), ('Moldova', 2), ('Azerbaijan', 2)]
#                                                              \____/                                                                                                                      \_____/                                         \______/
#after sorting                                                 /    \                                                                                                                      /     \                                         /      \
sorted_medals  = [('Sweden', 24), ('Germany', 16), ('Ireland', 10), ('Russia', 10), ('Spain', 9), ('Albania', 8), ('Lithuania', 7), ('Iceland', 6), ('Malta', 5), ('Italy', 5), ('Estonia', 4), ('Serbia', 4), ('Turkey', 4), ('Azerbaijan', 2), ('Moldova', 2)]

是否可能使用该operator模块？

Answer 1

在这个例子中,我使用lambda函数作为/ 的key参数:sort()sorted()

In [59]: sorted(list_of_medals, key=lambda x:(-x[1],x[0]))
Out[59]: 
[('Sweden', 24),
 ('Germany', 16),
 ('Ireland', 10),
 ('Russia', 10),
 ('Spain', 9),
 ('Albania', 8),
 ('Lithuania', 7),
 ('Iceland', 6),
 ('Italy', 5),
 ('Malta', 5),
 ('Estonia', 4),
 ('Serbia', 4),
 ('Turkey', 4),
 ('Azerbaijan', 2),
 ('Moldova', 2)]

的否定x[1]是需要在奖牌排序递减顺序而排序的国名升序的顺序(简单的设置reverse=True就不会做到这一点).

正如几位人士在评论中指出的那样,对复合键进行复杂排序的更通用方法是执行多个排序步骤.要执行此操作,请一次对一个组件进行排序,从最不重要的组件开始:

In [67]: temp = sorted(list_of_medals, key=itemgetter(0))

In [68]: sorted(temp, key=itemgetter(1), reverse=True)
Out[68]: 
[('Sweden', 24),
 ('Germany', 16),
 ('Ireland', 10),
 ('Russia', 10),
 ...

这取决于Python的排序是稳定的,这意味着比较相等的项永远不会重新排序.

Answer 2

您可以使用以下sorted功能：

sorted_by_medals = sorted(list_of_medals, key=lambda tup: (-tup[1], tup[0]))