按位运算符

~

1变0，0变1。

@H_404_7@let initialBits: UInt8 = 0b00001111 let invertedBits = ~initialBits // equals 11110000

$

全1得1，其他为0

@H_404_7@let firstSixBits: UInt8 = 0b11111100 let lastSixBits: UInt8 = 0b00111111 let middleFourBits = firstSixBits & lastSixBits // equals 00111100

|

有1得1，其他为0

@H_404_7@let someBits: UInt8 = 0b10110010 let moreBits: UInt8 = 0b01011110 let combinedbits = someBits | moreBits // equals 11111110

^

相异为1，相同为0

@H_404_7@let firstBits: UInt8 = 0b00010100 let otherBits: UInt8 = 0b00000101 let outputBits = firstBits ^ otherBits // equals 00010001

<<和>>

<<整体左移，右边填0；

>> 整体右移，左边填0。

<<和></p>>

@H_404_7@let shiftBits: UInt8 = 4 // 00000100 in binary shiftBits << 1 // 00001000 shiftBits << 2 // 00010000 shiftBits << 5 // 10000000 shiftBits << 6 // 00000000 shiftBits >> 2 // 00000001

算子函数

上面讲解的都是简单的运算符，下面的是为对象添加运算符，使之可计算。

符号在中间

@H_404_7@struct Vector2D { var x = 0.0,y = 0.0 } func + (left: Vector2D,right: Vector2D) -> Vector2D { return Vector2D(x: left.x + right.x,y: left.y + right.y) } let vector = Vector2D(x: 3.0,y: 1.0) let anotherVector = Vector2D(x: 2.0,y: 4.0) let combinedVector = vector + anotherVector // combinedVector is a Vector2D instance with values of (5.0,5.0)

前缀和后缀

前缀关键字prefix
后缀关键字postfix

@H_404_7@prefix func - (vector: Vector2D) -> Vector2D { return Vector2D(x: -vector.x,y: -vector.y) } let positive = Vector2D(x: 3.0,y: 4.0) let negative = -positive // negative is a Vector2D instance with values of (-3.0,-4.0) let alsoPositive = -negative // alsoPositive is a Vector2D instance with values of (3.0,4.0)

复合赋值运算符

这里用+=举例。

@H_404_7@func += (inout left: Vector2D,right: Vector2D) { left = left + right } var original = Vector2D(x: 1.0,y: 2.0) let vectorToAdd = Vector2D(x: 3.0,y: 4.0) original += vectorToAdd // original now has values of (4.0,6.0)

其他

参考资料

The Swift Programming Language (Swift 2.1)

文档修改记录

时间	描述
2015-11-1	根据 The Swift Programming Language (Swift 2.1)中的Classes and Structures总结

Swift高级运算符(Advanced Operators)