我有这个:
class Movies {
Name:String
Date:Int
}
我有一个 [Movies] 数组,如何按名称字母顺序对数组进行排序?我已经尝试过:
movieArr = movieArr.sorted{ $0 < $1 }
以及
movieArr = sorted(movieArr)
但这并不起作用,因为我没有访问 Movies 的名称属性。
sort
的闭包中,比较您想要排序的属性。像这样:movieArr.sorted { $0.name < $1.name }
或者在你想要绕过案例的情况下,可以采用以下方法:
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name
和date
,而不是Name
和Date
。
例如,在游乐场中:
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
将按照顺序[movieA, movieB, movieC]
排列。
channelsArray = channelsArray.sorted { (channel1, channel2) -> Bool in
let channelName1 = channel1.name
let channelName2 = channel2.name
return (channelName1.localizedCaseInsensitiveCompare(channelName2) == .orderedAscending)
}
使用Swift 3,你可以选择以下方式之一来解决你的问题。
Comparable
协议的Movie
类和 sorted(by:)
方法如果你的Movie
类不符合Comparable
协议,你必须在闭包中指定你想要使用数组的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
}
}
使用方法:
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]
*/
Comparable
协议的 Movie
类型和 sorted(by:)
方法如果你让你的 Movie
类型实现了 Comparable
协议,那么当你想使用 Array 的 sorted(by:)
方法时,你可以写出更加简洁的代码。
Movie
类型的声明:
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]
*/
Comparable
协议的Movie
类与sorted()
方法通过使你的Movie
类符合Comparable
协议,你可以使用数组的sorted()
方法代替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
}
}
使用方法:
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]
*/
movies.sorted(by: <)
和 movies.sorted()
之外,第二个和第三个有什么区别吗? - Kamaldeep singh Bhatiasorted(by:)
和sorted()
是两种不同的方法。您可以使用array.sorted()
作为array.sorted(by: <)
的替代方案。 - Imanou Petitsorted(by:)
和 sorted()
使用相同的类定义吗? - Kamaldeep singh Bhatia"1" "14""28""31""4""42""49"
- Krunal Nagvadia["1""4""14""28""28""31""42""49"]
。 - Krunal Nagvadialet sortArray = array.sorted(by: { $0.name.lowercased() < $1.name.lowercased() })
对于使用Swift 3的用户,接受答案的等效方法是:
movieArr.sorted { $0.Name < $1.Name }
由于未使用基于语言环境的比较进行排序,大多数答案都是错误的。请查看localizedStandardCompare()。
已排序数组
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!
}*
.lowercaseString
可以解决这个问题。 - Matthieu Rieglersorted
了:D。 - dvp.petrov