Swift：按字母顺序对对象数组进行排序

我有这个：

class Movies {
  Name:String
  Date:Int
}

和[电影]数组。如何按名称的字母顺序对数组进行排序？我试过了：

movieArr = movieArr.sorted{ $0 < $1 }

和

movieArr = sorted(movieArr)

但这不起作用，因为我没有访问电影的名称属性。

在传递给的闭包中sort，比较要排序的属性。像这样：

movieArr.sorted { $0.name < $1.name }

或以下要绕过案例的案例：

movieArr.sorted { $0.name.lowercased() < $1.name.lowercased() }

旁注：通常，只有类型以大写字母开头；我建议使用nameand date，而不是Nameand Date。

例如，在操场上：

class Movie {
    let name: String
    var date: Int?

    init(_ name: String) {
        self.name = name
    }
}

var movieA = Movie("A")
var movieB = Movie("B")
var movieC = Movie("C")

let movies = [movieB, movieC, movieA]
let sortedMovies = movies.sorted { $0.name < $1.name }
sortedMovies

sortedMovies 将按顺序 [movieA, movieB, movieC]

Swift5更新

channelsArray = channelsArray.sorted { (channel1, channel2) -> Bool in
            let channelName1 = channel1.name
            let channelName2 = channel2.name
            return (channelName1.localizedCaseInsensitiveCompare(channelName2) == .orderedAscending)

使用Swift 3，您可以选择以下方法之一来解决问题。

1. sorted(by:​)与Movie不符合Comparable协议的类一起使用

如果您的Movie类不符合Comparable协议，则必须在闭包中指定要使用Array sorted(by:​)方法的属性。

Movie 类声明：

import Foundation

class Movie: CustomStringConvertible {

    let name: String
    var date: Date
    var description: String { return name }

    init(name: String, date: Date = Date()) {
        self.name = name
        self.date = date
    }

}

用法：

let avatarMovie = Movie(name: "Avatar")
let titanicMovie = Movie(name: "Titanic")
let piranhaMovie = Movie(name: "Piranha II: The Spawning")

let movies = [avatarMovie, titanicMovie, piranhaMovie]
let sortedMovies = movies.sorted(by: { $0.name < $1.name })
// let sortedMovies = movies.sorted { $0.name < $1.name } // also works

print(sortedMovies)

/*
prints: [Avatar, Piranha II: The Spawning, Titanic]
*/

2. sorted(by:​)与Movie符合Comparable协议的类一起使用

但是，通过使您的Movie类符合Comparable协议，当您要使用Array的sorted(by:​)方法时，您可以得到非常简洁的代码。

Movie 类声明：

import Foundation

class Movie: CustomStringConvertible, Comparable {

    let name: String
    var date: Date
    var description: String { return name }

    init(name: String, date: Date = Date()) {
        self.name = name
        self.date = date
    }

    static func ==(lhs: Movie, rhs: Movie) -> Bool {
        return lhs.name == rhs.name
    }

    static func <(lhs: Movie, rhs: Movie) -> Bool {
        return lhs.name < rhs.name
    }

}

用法：

let avatarMovie = Movie(name: "Avatar")
let titanicMovie = Movie(name: "Titanic")
let piranhaMovie = Movie(name: "Piranha II: The Spawning")

let movies = [avatarMovie, titanicMovie, piranhaMovie]
let sortedMovies = movies.sorted(by: { $0 < $1 })
// let sortedMovies = movies.sorted { $0 < $1 } // also works
// let sortedMovies = movies.sorted(by: <) // also works

print(sortedMovies)

/*
 prints: [Avatar, Piranha II: The Spawning, Titanic]
 */

3. sorted()与Movie符合Comparable协议的类一起使用

通过使您的Movie类符合Comparable协议，您可以使用Array的sorted()方法替代sorted(by:​)。

Movie 类声明：

import Foundation

class Movie: CustomStringConvertible, Comparable {

    let name: String
    var date: Date
    var description: String { return name }

    init(name: String, date: Date = Date()) {
        self.name = name
        self.date = date
    }

    static func ==(lhs: Movie, rhs: Movie) -> Bool {
        return lhs.name == rhs.name
    }

    static func <(lhs: Movie, rhs: Movie) -> Bool {
        return lhs.name < rhs.name
    }

}

用法：

let avatarMovie = Movie(name: "Avatar")
let titanicMovie = Movie(name: "Titanic")
let piranhaMovie = Movie(name: "Piranha II: The Spawning")

let movies = [avatarMovie, titanicMovie, piranhaMovie]
let sortedMovies = movies.sorted()

print(sortedMovies)

/*
 prints: [Avatar, Piranha II: The Spawning, Titanic]
 */

let sortArray =  array.sorted(by: { $0.name.lowercased() < $1.name.lowercased() })

对于使用Swift 3的用户，可接受的答案的等效方法是：

movieArr.sorted { $0.Name < $1.Name }

排序数组Swift 4.2

arrayOfRaces = arrayOfItems.sorted(by: { ($0["raceName"] as! String) < ($1["raceName"] as! String) })

*import Foundation
import CoreData


extension Messages {

    @nonobjc public class func fetchRequest() -> NSFetchRequest<Messages> {
        return NSFetchRequest<Messages>(entityName: "Messages")
    }

    @NSManaged public var text: String?
    @NSManaged public var date: Date?
    @NSManaged public var friends: Friends?

}

    //here arrMessage is the array you can sort this array as under bellow 

    var arrMessages = [Messages]()

    arrMessages.sort { (arrMessages1, arrMessages2) -> Bool in
               arrMessages1.date! > arrMessages2.date!
    }*