是否有任何方式来模拟[NSString stringWithFormat:@“%p”,myVar],从Objective-C,在新的Swift语言?

例如:

let str = "A String"
println(" str value \(str) has address: ?")

当前回答

注意:这是针对引用类型的。

斯威夫特:4/5

print(Unmanaged.passUnretained(someVar).toOpaque())

打印someVar的内存地址。 (感谢@Ying)


斯威夫特3.1:

print(Unmanaged<AnyObject>.passUnretained(someVar as AnyObject).toOpaque())

打印someVar的内存地址。


其他回答

这当然不是最快或最安全的方法。但这对我很管用。这将允许任何nsobject子类采用此属性。

public extension NSObject {
    public var memoryAddress : String? {
        let str = "\(self.self)".components(separatedBy: ": ")
        guard str.count > 1 else { return nil }
        return str[1].replacingOccurrences(of: ">", with: "")            
    }
}

//usage 
let foo : String! = "hello"
Swift.print(foo.memoryAddress) // prints 0x100f12980

在Swift4 about Array中:

    let array1 = [1,2,3]
    let array2 = array1
    array1.withUnsafeBufferPointer { (point) in
        print(point) // UnsafeBufferPointer(start: 0x00006000004681e0, count: 3)
    }
    array2.withUnsafeBufferPointer { (point) in
        print(point) // UnsafeBufferPointer(start: 0x00006000004681e0, count: 3)
    }

斯威夫特2

这现在是标准库的一部分:unsafeAddressOf。

/// Return an UnsafePointer to the storage used for `object`.  There's
/// not much you can do with this other than use it to identify the
/// object

斯威夫特3

对于Swift 3,使用withUnsafePointer:

var str = "A String"
withUnsafePointer(to: &str) {
    print(" str value \(str) has address: \($0)")
}

引用类型:

获取引用类型的内存地址是有意义的,因为它表示标识。 ===标识运算符用于检查两个对象是否指向同一个引用。 使用ObjectIdentifier获取内存地址

代码:

class C {}

let c1 = C()
let c2 = c1

//Option 1:
print("c1 address: \(Unmanaged.passUnretained(c1).toOpaque())") 

//Option 2:
let o1 = ObjectIdentifier(c1)
let o2 = ObjectIdentifier(c2)

print("o1 -> c1 = \(o1)")
print("o2 -> c2 = \(o2)")

if o1 == o2 {
    print("c1 = c2")
} else {
    print("c1 != c2")
}

//Output:
//c1 address: 0x000060c000005b10
//o1 -> c1 = ObjectIdentifier(0x000060c000005b10)
//o2 -> c2 = ObjectIdentifier(0x000060c000005b10)
//c1 = c2

值类型:

获取值类型的内存地址的需求并不太重要(因为它是一个值),重点将更多地放在值的相等性上。

如果你只是想在调试器中看到这个,而不做任何其他事情,实际上没有必要获得Int指针。要在内存中获取对象地址的字符串表示形式,只需使用如下方法:

public extension NSObject { // Extension syntax is cleaner for my use. If your needs stem outside NSObject, you may change the extension's target or place the logic in a global function
    public var pointerString: String {
        return String(format: "%p", self)
    }
}

使用示例:

print(self.pointerString, "Doing something...")
// Prints like: 0x7fd190d0f270 Doing something...

此外,请记住,你可以简单地打印一个对象,而不重写它的描述,它将显示它的指针地址与更多的描述性(如果经常是隐晦的)文本。

print(self, "Doing something else...")
// Prints like: <MyModule.MyClass: 0x7fd190d0f270> Doing something else...
// Sometimes like: <_TtCC14__lldb_expr_668MyModule7MyClass: 0x7fd190d0f270> Doing something else...