1. i/j – division – if both are ints, result is int, represen9ng quo9ent without remainder
e.g. 3/2 = 1 3.0/2 = 1.5
2. --2 >>> 2
3. ‘a‘ * 2 >>> ‘aa‘
4 . ‘abc‘[-1] returns ‘c‘
5. ‘world‘[:-1] returns ‘worl‘
原文：http://www.cnblogs.com/njuzwr/p/4467029.html