如何在没有"可选"的情况下从plist打印字符串？

Question

我从plist中的字典加载一个值但是当我将它打印到控制台时,它会打印:可选(星期一标题)而不仅仅是"星期一标题".

如何在打印时摆脱我的值的Optional()？

var plistPath = NSBundle.mainBundle().pathForResource("days", ofType: "plist")
var plistArray = NSArray(contentsOfFile: plistPath!) as NSArray!

    for obj: AnyObject in plistArray {
        if var dicInfo = obj as? NSDictionary {
            let todayTitle: AnyObject? = dicInfo.valueForKey("Title")
            println(todayTitle)
        }
    }    

Answer 1

摆脱它的一种方法Optional是使用感叹号:

println(todayTitle!)

但是,只有在您确定值存在的情况下才应该这样做.另一种方法是打开并使用条件,如下所示:

if let theTitle = todayTitle {
    println(theTitle)
}

将此程序粘贴到runswiftlang中进行演示:

let todayTitle : String? = "today"
println(todayTitle)
println(todayTitle!)
if let theTitle = todayTitle {
    println(theTitle)
}

Answer 2

经过一些尝试,我认为这种方式更好.

(variableName ?? "default value")!

使用??默认值,然后使用!对折可选变量.

这是一个例子,

var a:String? = nil
var b:String? = "Hello"

print("varA = \( (a ?? "variable A is nil.")! )")
print("varB = \( (b ?? "variable B is nil.")! )")

它会打印出来

varA = variable A is nil.
varB = Hello