具体的解决方案是使用带有步长的切片:
source = ['1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b']
list1 = source[::4]
list2 = source[1::4]
list3 = source[2::4]
list4 = source[3::4]
source[::4]
选取每隔4个元素的元素,从索引0开始计数;其他切片只会改变起始索引。
通用解决方案是使用循环进行切片,并将结果存储在外部列表中;列表推导式可以很好地完成这个任务:
def slice_per(source, step):
return [source[i::step] for i in range(step)]
演示:
>>> source = ['1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b']
>>> source[::4]
['1', '5', '9']
>>> source[1::4]
['2', '6', 'a']
>>> def slice_per(source, step):
... return [source[i::step] for i in range(step)]
...
>>> slice_per(source, 4)
[['1', '5', '9'], ['2', '6', 'a'], ['3', '7', 'b'], ['4', '8']]
>>> slice_per(source, 3)
[['1', '4', '7', 'a'], ['2', '5', '8', 'b'], ['3', '6', '9']]