a +=b ==> a = a + b
a -=b ==> a = a - b
a *=b ==> a = a * b
a /=b ==> a = a / b
a %=b ==> a = a % b #取模赋值运算
a **=b ==> a = a ** b #幂赋值运算
a //= ==> a = a // b #整除赋值运算
具体例子如下
数据运算
原文：http://www.cnblogs.com/cheng662540/p/7906630.html
