python按位运算的奇怪结果

Question

谁能解释一下？我对以下结果感到非常困惑。非常感谢！

为什么这不起作用！？？？

`i = 2
table[i] = i&1 + table[i>>1] `

以下作品

`tmp = i&1
 table[i] = tmp + table[i>>1]`

Answer 1

这是因为括号分组和 & 具有较少的优先级：这是一个如何工作的示例：

2& will not happen until 2+ 2 >> 2
In [569]: 2&2 + 2>>2                                                                                                                                                                           
Out[569]: 0

Here we use the and in parens first, before adding to 2>>2
In [570]: (2&2) + 2>>2                                                                                                                                                                         
Out[570]: 1

Here's what the operator precedence looks like for the original operation:
In [571]: 2&(2 + 2>>2)                                                                                                                                                                         
Out[571]: 0