Swift - 按 id 比较 2 个数组，并合并到新的排序数组中答案

【问题标题】：Swift - comparing 2 arrays by id, and merge into new sorted ArraySwift - 按 id 比较 2 个数组，并合并到新的排序数组中
【发布时间】：2018-04-21 01:57:55
【问题描述】：

我有 2 个数组：

Arr1 = [ ["name": "Player1", "userId": "11", "Score": 9, "picURL": "https://1111"], ["name": "Player2", "userId": "12", "Score": 6, "picURL": "https://2222"], ["name": "Player3", "userId": "13", "Score": 4, "picURL": "https://3333"], ["name": "Player4", "userId": "14", "Score": 8, "picURL": "https://4444"],  ["name": "Player5", "userId": "15", "Score": 1, "picURL": "https://5555"] ]
Arr2 = [["userId": "12"], ["userId": "13"], ["userId": "15"]]

如何按“userId”映射此数组，以得到按“分数”按降序排序的数组，如下所示：

resultArr = [["name": "Player2", "Score": 6, "picURL": "https://2222], ["name": "Player3", "Score": 4, "picURL": "https://3333], ["name": "Player5", "Score": 1, "picURL": "https://5555] ]

【问题讨论】：

标签： arrays swift sorting mapping

【解决方案1】：

let result = Arr1.filter { player in Arr2.contains(where: { $0["userId"] == player["userId"] as? String }) }
                 .sorted(by: { $0["Score"] as! Int > $1["Score"] as! Int })

【讨论】：

太棒了！谢谢！

【解决方案2】：

您可以先将 Arr1 更改为数组字典，以便以后更快地搜索，然后使用 Arr2 过滤该字典，然后再使用排序对过滤后的数组进行排序。

let Arr1 = [ ["name": "Player1", "userId": "11", "Score": 9, "picURL": "https://1111"], ["name": "Player2", "userId": "12", "Score": 6, "picURL": "https://2222"], ["name": "Player3", "userId": "13", "Score": 4, "picURL": "https://3333"], ["name": "Player4", "userId": "14", "Score": 8, "picURL": "https://4444"],  ["name": "Player5", "userId": "15", "Score": 1, "picURL": "https://5555"]]

// reducing array of dictionaries to dictioonary of array
let dict = Arr1.reduce([String: [String:Any]]()) { (dict, arrayElement) -> [String: [String:Any]] in
    var dict = dict
    let userId = arrayElement["userId"] as! String
    var arrayElement = arrayElement
    arrayElement.removeValue(forKey: "userId")
    dict[userId] = arrayElement
    return dict
}

let Arr2 = [["userId": "12"], ["userId": "13"], ["userId": "15"]]

// Using flat map to create an array of dictionaries where userid exists in Arr2 and then sorting that array on Score
let filtered = Arr2.flatMap { (element) -> [String:Any]? in
    guard let userId = element["userId"] else {
        return nil
    }
    return dict[userId]
    }.sorted { (d1, d2) -> Bool in
        return d1["Score"] as! Int > d2["Score"] as! Int
}

print(filtered) // [["name": "Player2", "Score": 6, "picURL": "https://2222"], ["name": "Player3", "Score": 4, "picURL": "https://3333"], ["name": "Player5", "Score": 1, "picURL": "https://5555"]]

【讨论】：

感谢您的解决方案！