The + operator concatenates lists:
Similarly, the * operator repeats a list a given number of items:
List slices
The slice operator also works on lists:
If you omit the first index, the slice starts at the beginning. If you omit the second, the slice goes to the end. So if you omit both, the slice is a copy of the whole list.
from Thinking in Python
List operations,布布扣,bubuko.com
原文：http://www.cnblogs.com/ryansunyu/p/3841107.html