转换很简单:

let float = Float(1.1) // 1.1
let int = Int(float) // 1

但这并不安全:

let float = Float(Int.max) + 1
let int = Int(float)

将由于一次漂亮的碰撞:

fatal error: floating point value can not be converted to Int because it is greater than Int.max

所以我已经创建了一个处理溢出的扩展:

extension Double {
    // If you don't want your code crash on each overflow, use this function that operates on optionals
    // E.g.: Int(Double(Int.max) + 1) will crash:
    // fatal error: floating point value can not be converted to Int because it is greater than Int.max
    func toInt() -> Int? {
        if self > Double(Int.min) && self < Double(Int.max) {
            return Int(self)
        } else {
            return nil
        }
    }
}


extension Float {
    func toInt() -> Int? {
        if self > Float(Int.min) && self < Float(Int.max) {
            return Int(self)
        } else {
            return nil
        }
    }
}

我希望这能帮助到一些人

你可以像这样进行类型转换:

 var float:Float = 2.2
 var integer:Int = Int(float)

使用函数样式的转换(参见“Swift编程语言”中的“整数和浮点转换”一节)。(iTunes链接))

  1> Int(3.4)
$R1: Int = 3

转换很简单:

let float = Float(1.1) // 1.1
let int = Int(float) // 1

但这并不安全:

let float = Float(Int.max) + 1
let int = Int(float)

将由于一次漂亮的碰撞:

fatal error: floating point value can not be converted to Int because it is greater than Int.max

所以我已经创建了一个处理溢出的扩展:

extension Double {
    // If you don't want your code crash on each overflow, use this function that operates on optionals
    // E.g.: Int(Double(Int.max) + 1) will crash:
    // fatal error: floating point value can not be converted to Int because it is greater than Int.max
    func toInt() -> Int? {
        if self > Double(Int.min) && self < Double(Int.max) {
            return Int(self)
        } else {
            return nil
        }
    }
}


extension Float {
    func toInt() -> Int? {
        if self > Float(Int.min) && self < Float(Int.max) {
            return Int(self)
        } else {
            return nil
        }
    }
}

我希望这能帮助到一些人

你可以像这样在Swift中将Float转换为Int:

var myIntValue:Int = Int(myFloatValue)
println "My value is \(myIntValue)"

你也可以通过@paulm的评论来实现这个结果:

var myIntValue = Int(myFloatValue)

这里介绍的大多数解决方案对于较大的值都会崩溃，不应该在生产代码中使用。

如果你不关心非常大的值，使用这段代码来夹紧Double到max/min Int值。

let bigFloat   = Float.greatestFiniteMagnitude
let smallFloat = -bigFloat

extension Float {
    func toIntTruncated() -> Int {
        let maxTruncated  = min(self, Float(Int.max).nextDown)
        let bothTruncated = max(maxTruncated, Float(Int.min))
        return Int(bothTruncated)
    }
}

// This crashes:
// let bigInt = Int(bigFloat)

// this works for values up to 9223371487098961920
let bigInt   = bigFloat.toIntTruncated()
let smallInt = smallFloat.toIntTruncated()