Swift - 按键降序排序字典

Question

我正在尝试按键(降序)对字典进行排序，这是我的代码:

var codes = [String:String]()

codes["2"] = "Bitten by turtle"
codes["6"] = "Burn due to water-skis on fire"
codes["12"] = "Walked into lamppost"
codes["24"] = "Bizarre personal appearance"
codes["100"] = "Fall in (into) bucket of water causing drowning and submersion"


let unsortedCodeKeys = Array(codes.keys)
print(unsortedCodeKeys)

let sortedCodeKeys = unsortedCodeKeys.sort(<)

但是，当您打印 sortedCodeKeys 时，它仍然不是降序。怎么会？如何按降序对键进行排序？ (所有键都是整数)。

Answer 1

正如 ayaio 和 Martin R 所说，您的键必须是 Int 才能按照您的意愿对字典进行排序。您还应该对 sortedCodeKeys 常量做一个小的更改，如下所示:

    var codes = [Int:String]()

    codes[2] = "Bitten by turtle"
    codes[6] = "Burn due to water-skis on fire"
    codes[12] = "Walked into lamppost"
    codes[24] = "Bizarre personal appearance"
    codes[100] = "Fall in (into) bucket of water causing drowning and submersion"

    let sortedCodeKeys = codes.sorted(by: { $0.key > $1.key })
    print(sortedCodes)

//returns [(key: 100, value: "Fall in (into) bucket of water caused drowning and submersion"), (key: 24, value: "Bizarre personal appearance"), (key: 12, value : "Walked into lamppost"), (key: 6, value: "Burn due to water-skis on fire"), (key: 2, value: "Bittened by turtle")].