pythonのスライシングについて([::-1],[low:high:step]などについて)

[low:high:step]： lowからhighまでstepごとに選択

>>> l=[1,2,3,4,5,6,7,8,9]
>>> l[4::2]
[5, 7, 9]
>>> l[4::1]
[5, 6, 7, 8, 9]
>>> l[4::3]
[5, 8]
>>> l[::3]
[1, 4, 7]
>>> l[:-1]
[1, 2, 3, 4, 5, 6, 7, 8]
>>> l[::-1]
[9, 8, 7, 6, 5, 4, 3, 2, 1]
>>> l[2:7:2]
[3, 5, 7]
>>> l[2:8:2]
[3, 5, 7]
>>> l[2:6:2]
[3, 5]
>>> l[2:7:3]
[3, 6]
>>> l[1:7:3]
[2, 5]
>>> l[1:8:3]
[2, 5, 8]
>>>