python列表切片

#正数索引，默认间隔为1，从左向右取，索引范围依次为0，1，2，3，，，，9
>>> print lista[1:4]
[1, 2, 3]
>>> print lista[1:7:2]
[1, 3, 5]
>>> 
>>> 
#负数索引，默认间隔为1，从左向右取，索引依次为-10，-9，-8，，，，-1
>>> 
>>> print lista[-1:-3]
[]
>>> print lista[-1:]
[9]
>>> print lista[-3:-1]
[7, 8]
>>> 
#间隔为负数，先翻转再从左向右取，索引依次是-1，-2，-3，，，，-10
>>> print lista[::-1]
[9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
>>> print lista[:-5:-1]
[9, 8, 7, 6]
>>> print lista[-6:-1:-1]
[]
>>> print lista[-1:-6:-1]
[9, 8, 7, 6, 5]
>>>