Python 3.2.3 (default, Apr 11 2012, 07:15:24) [MSC v.1500 32 bit (Intel)] on win
32
Type "help", "copyright", "credits" or "license" for more information.
>>> u = [4, 5, 6, 7, 8, 9]
>>> u[1::1] = [3, 2, 1, 0]
>>> u
[4, 3, 2, 1, 0]
>>> u[9:0:-1] = [8, 7, 6, 5]
>>> u
[4, 5, 6, 7, 8]
>>> u[9:0:-1] = [16, 12, 8]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ValueError: attempt to assign sequence of size 3 to extended slice of size 4
>>> u
[4, 5, 6, 7, 8]
>>>
预期行为:最终赋值语句没有抛出异常;u
应该在最后一行打印为[4, 8, 12, 16]
.
我可以分配一个步长为 1 的扩展切片,即使我分配的可迭代是“错误的长度”。那么为什么我不能分配给步长为 -1 的扩展切片并让它以明显的方式工作呢?