将NSNumber转换为StringSwift2-ConvertNSNumberintoStringSwift2

14  

Since the numeric result is supposed to be an Int anyway you can omit the NSNumber detour.

因为数字结果应该是Int，所以你可以省略NSNumber绕道。

let tempNumber = userInfoDict.valueForKey("designation") as! Int 
let stringTemp = String(tempNumber)

Side note: Since userInfoDict seems to be a dictionary, don't use the key-value coding method valueForKey: unless you really need the special functionality.
Either use key subscripting (recommended) userInfoDict["designation"] or objectForKey:

旁注：由于userInfoDict似乎是一个字典，所以不要使用键值编码方法valueForKey：除非你真的需要特殊的功能。使用密钥下标（推荐）userInfoDict [“designation”]或objectForKey：

12  

You'll have to format the NSNumber's doubleValue member to a string before outputting.

在输出之前，您必须将NSNumber的doubleValue成员格式化为字符串。

let tempNumber:NSNumber = 6.0
let s:String = String(format:"%f", tempNumber.doubleValue) //formats the string to accept double/float
print(s)

3  

You can refer the following code to see how NSNumber can be converted into NSString.

您可以参考以下代码以了解如何将NSNumber转换为NSString。

 let a = 10
let aString = String(a)

Its better to avoid complicated codes for simple stuffs.

最好避免简单的东西复杂的代码。