Swift：按字母顺序排列对象的数组

我有这个：

class Movies { Name:String Date:Int } 

和一组[电影]。 如何按名称按字母顺序排列数组？ 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。

Answer 1

在closures时，你要通过sort ，比较你想sorting的属性。 喜欢这个：

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

旁注：通常只有types以大写字母开头; 我build议使用name和date ，而不是Name和Date 。

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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]

Answer 2

使用Swift 3，您可以select以下方法之一来解决您的问题。

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

如果Movie类不符合Comparable协议，则必须在您的闭包中指定您希望使用Array的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] */ 

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2.使用符合Comparable协议的Movie类来sorted(by:​) Comparable

但是，通过使Movie类符合Comparable协议，当您想使用Array的sorted(by:​)方法时，可以有一个非常简洁的代码。

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] */ 

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3.使用与符合Comparable协议的Movie类一起使用sorted()

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

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] */ 

Answer 3

对于那些使用Swift 3的人来说，接受答案的等价方法是：

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