Comments (7)
记住这个规则:一个数加1然后再取相反数。
比如:
- ~3就变成-(3+1)=-4
- ~(-6)就是-(-6+1)=5
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位运算 NOT 由否定号(~)表示,它是 ECMAScript 中为数不多的与二进制算术有关的运算符之一
位运算 NOT 是三步的处理过程:
1.把运算数转换成 32 位数字
2.把二进制数转换成它的二进制反码
3.把二进制数转换成浮点数
位运算 NOT 实质上是对数字求负,然后减 1;4 >-4>-5
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@rodickmini 先把"4"隐式转换成Number型,再进行计算
~相当于取反 再减1
~4 = -5
~-5 = 5 - 1 = 4
参见红宝书40页 按位非
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记得哪里看的,非负数取整Math.floor()
也可以使用~~()
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~操作符 转换成二进制后 取反数。
4:00000000000000000000000000000100 => 11111111111111111111111111111011 =>-5
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-5 按位非
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问:为什么~~"4"
等于4
?
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