python列表sort方法的两个参数key, reverse

Posted 2020-08-07

使用列表的sort方法可以进行排序，其中有两个参数用来表示排序的方式，代码：

In [7]: a = [‘x11‘,‘abc323‘,‘e26‘,‘112ddd‘]

In [8]: a.sort(key=len, reverse=True)

In [9]: a
Out[9]: [‘abc323‘, ‘112ddd‘, ‘x11‘, ‘e26‘]

In [10]: a.sort(key=lambda x:x[-1])

In [11]: a
Out[11]: [‘x11‘, ‘abc323‘, ‘e26‘, ‘112ddd‘]

In [12]: a = zip(range(10), range(10)[::-1])

In [13]: a
Out[13]: <zip at 0x518d308>

In [14]: b = list(a)

In [15]: b
Out[15]:
[(0, 9),
 (1, 8),
 (2, 7),
 (3, 6),
 (4, 5),
 (5, 4),
 (6, 3),
 (7, 2),
 (8, 1),
 (9, 0)]

In [17]: b.sort(key=lambda x:x[1])

In [18]: b
Out[18]:
[(9, 0),
 (8, 1),
 (7, 2),
 (6, 3),
 (5, 4),
 (4, 5),
 (3, 6),
 (2, 7),
 (1, 8),
 (0, 9)]

参数key可以是：key=int，key=len， key=lambda...