Swift 4：

Question

我希望[String：String]中的convert [（key：String，value：String）]可以吗？如果是，我怎么做？感谢

var KeyValuePair: [(key: String, value: String)] = [(key: "2017 01 04", value: "143.65"), (key: "2017 01 05", value: "140.78"), (key: "2017 01 06", value: "150.23")]

in

var dictionary: [String:String] =  ["2017 01 04":"143.65", "2017 01 05":"140.78", "2017 01 06":"150.23"]

Answer 1

您只需遍历元组数组并使用元组的值设置字典的键值对。

var keyValuePairs: [(key: String, value: String)] = [(key: "2017 01 04", value: "143.65"), (key: "2017 01 05", value: "140.78"), (key: "2017 01 06", value: "150.23")]

var dictionary = [String:String]()
keyValuePairs.forEach{
    dictionary[$0.0] = $0.1
    //since you have named tuples, you could also write dictionary[$0.key] = $0.value
}
print(dictionary)

请确保符合Swift命名约定，该约定是变量名称的较低值。

Answer 2

Swift 4：

如果您确定这些键是唯一的，则可以使用Dicitonary.init(uniqueKeysWithValues:)：

let dict = Dicitonary(uniqueKeysWithValues: keyValuePairs)

否则，您可以改为使用Dictionary.init(_:uniquingKeysWith:)，这可以指定如何处理碰撞。

let dict = Dictionary(keyValuePairs, uniquingKeysWith: { previous, new in
    return new //always takes the newest value for a given key
})

Answer 3

一线功能方法是：

let dictionary = keyValuePair.reduce([String : String]())
                 {  acc, item in
                    var output = acc
                    output.updateValue(item.value, forKey: item.key)
                    return output
                 }

您还可以通过实施extension到Dictionary

来实现目标

extension Dictionary
{
    func appending(value: Value, key: Key) -> Dictionary
    {
        var mutable = self
        mutable.updateValue(value, forKey: key)
        return mutable
    }
}

let dictionary = keyValuePair.reduce([String : String]()) { $0.appending(value: $1.value, key: $1.key) }

在[String：String]中转换[（key：String，value：String）]

3 个答案:

Swift 4：