了解PHP和放大器; （符号，按位与）运算符 [英] Understanding PHP & (ampersand, bitwise and) operator

问题描述

我经常使用（$ VAR和放大器; 1）在我的code，它返回true，如果 $ VAR 是奇数和虚假如果它是一个偶数。

I often use ($var & 1) in my code, which returns true if $var is an odd number and false if it's an even number.

但什么是＆放大器;实际上做？

But what does "&" actually do?

推荐答案

＆安培;是二进制的和。如果你有一个二进制值，您和与另一个二进制值，那么结果将是按位和的他们俩。举个例子：

& is binary and. If you have a binary value, and you and with another binary value, then the result will be the bitwise and of the two. An example:

  01101010
& 01011001
= 01001000

最右边的位可以是一个1（在此情况下的数量是奇数），或者它是一个0，在这种情况下的数量是偶数。如果您＆安培; 1的数字，你只看至少显著位，而如果检查的数量是1或0。正如其他人所说，看位运算符的信息他们是如何工作的。

The rightmost bit is either a 1 (and in that case the number is an odd number) or it is a 0, in which case the number is even. If you & a number with 1, you only look at the least significant bit, and the if checks if the number is a 1 or a 0. As others have mentioned, look at the bitwise operators for info on how they work.

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