我有一个简单的字典,它的定义如下:

var dict : NSDictionary = [ 1 : "abc", 2 : "cde"]

现在我想在这个字典中添加一个元素:3:"efg"

我如何能追加3:“efg”到这个现有的字典?


当前回答

到目前为止,我发现的最好的方法是通过使用Swift的高阶函数之一来将数据追加到字典中。“减少”。遵循以下代码片段:

newDictionary = oldDictionary.reduce(*newDictionary*) { r, e in var r = r; r[e.0] = e.1; return r }

@Dharmesh在你的情况下,

newDictionary = dict.reduce([3 : "efg"]) { r, e in var r = r; r[e.0] = e.1; return r }

请让我知道,如果你发现任何问题在使用上述语法。

其他回答

斯威夫特 3+

向Dictionary分配新值的示例。你需要声明它为NSMutableDictionary:

var myDictionary: NSMutableDictionary = [:]
let newValue = 1
myDictionary["newKey"] = newValue
print(myDictionary)

Swift 3 - xcode 8.1

var dictionary =  [Int:String]() 

dictionary.updateValue(value: "Hola", forKey: 1)
dictionary.updateValue(value: "Hello", forKey: 2)
dictionary.updateValue(value: "Aloha", forKey: 3)

所以,你的字典包含:

字典[1:Hola, 2: Hello, 3: Aloha]

如果你想修改或更新NSDictionary那么 首先,将它类型转换为NSMutableDictionary

let newdictionary = NSDictionary as NSMutableDictionary

然后简单地使用

 newdictionary.setValue(value: AnyObject?, forKey: String)

Swift 5快乐编码

var tempDicData = NSMutableDictionary()

for temp in answerList {
    tempDicData.setValue("your value", forKey: "your key")
}
For whoever reading this for swift 5.1+

  // 1. Using updateValue to update the given key or add new if doesn't exist


    var dictionary = [Int:String]()    
    dictionary.updateValue("egf", forKey: 3)



 // 2. Using a dictionary[key]

    var dictionary = [Int:String]()    
    dictionary[key] = "value"



 // 3. Using subscript and mutating append for the value

    var dictionary = [Int:[String]]()

    dictionary[key, default: ["val"]].append("value")