Question

在网络上进行了大量研究后，我尝试了几种解决方案，但这行不通吗？我想根据LeagueCode属性对数组排序，这是我的代码：

var teams = [Team]()

    dbReference.child(FBDatabaseKeys.teams).observeSingleEvent(of: .value) { (snapshot) in
        for nameTeam in snapshot.children.allObjects as! [DataSnapshot] {
            let value = nameTeam.value as? NSDictionary

            let team = Team(
                capitanId: value?[FBDatabaseKeys.Teams.captainID] as! String,
                leagueCode: value?[FBDatabaseKeys.Teams.leagueCode] as? String ?? value?["leageCode"] as! String,
                playersIds: [""], //todo retrieve data to array
                teamName: value?[FBDatabaseKeys.Teams.teamName] as! String,
                imageUrl: value?[FBDatabaseKeys.Teams.imageUrl] as! String,
                groupMoto: value?[FBDatabaseKeys.Teams.teamMoto] as! String,
                totalScore: String(format: "%@", value?[FBDatabaseKeys.Teams.totalScore] as? CVarArg ?? "") ,
                totalTickets: String(format: "%@", value?[FBDatabaseKeys.Teams.totalTickets] as? CVarArg ?? "")
            )

            if team.leagueCode == self.currentPlayer.leagueCode{
                teams.append(team)
            }
        }

        teams = teams.sort {
            Int($0.leagueCode)! < Int($1.leagueCode)!
        } as! [Team]

        //Sort array by property score
        completion(teams)
    }

错误：

错误：（204，27）无法将类型'（）'的值分配给类型'[Team]'

这是我的对象：

struct Team {
let capitanId: String
let leagueCode: String
let playersIds: [String]
let teamName: String
let imageUrl: String
let groupMoto: String
let totalScore: String
let totalTickets: String

感谢您的帮助

Answer 1

您需要

teams  = teams.sorted {
  Int($0.leagueCode)! < Int($1.leagueCode)!
}

或仅mutating

teams.sort {
    Int($0.leagueCode)! < Int($1.leagueCode)!
}

https://developer.apple.com/documentation/swift/array/2296815-sorted https://developer.apple.com/documentation/swift/array/2296801-sort

//

dbReference.child(FBDatabaseKeys.teams).observeSingleEvent(of: .value) { (snapshot) in
        for nameTeam in snapshot.children.allObjects as! [DataSnapshot] {
            let value = nameTeam.value as? NSDictionary

            let team = Team(
                capitanId: value?[FBDatabaseKeys.Teams.captainID] as! String,
                leagueCode: value?[FBDatabaseKeys.Teams.leagueCode] as? String ?? value?["leageCode"] as! String,
                playersIds: [""], //todo retrieve data to array
                teamName: value?[FBDatabaseKeys.Teams.teamName] as! String,
                imageUrl: value?[FBDatabaseKeys.Teams.imageUrl] as! String,
                groupMoto: value?[FBDatabaseKeys.Teams.teamMoto] as! String,
                totalScore: String(format: "%@", value?[FBDatabaseKeys.Teams.totalScore] as? CVarArg ?? "") ,
                totalTickets: String(format: "%@", value?[FBDatabaseKeys.Teams.totalTickets] as? CVarArg ?? "")
            )

            if team.leagueCode == self.currentPlayer.leagueCode{
                teams.append(team)
            }
        }

        teams.sort {
            Int($0.leagueCode)! < Int($1.leagueCode)!
        }  


        completion(teams)
}

Answer 2

错误消息

无法分配'（）'类型的值

清楚地说sort函数不返回任何内容。数组按位置排序。

并且不需要转换为Int。您可以使用localizedStandardCompare

对字符串进行数字排序

teams.sort {
    $0.leagueCode.localizedStandardCompare($1.leagueCode) == .orderedAscending
}

Swift：按属性对列表对象进行排序

2 个答案: