‏Comparable والترتيب

ما هو Comparable؟

الالتزام باستخدام <

struct Version: Comparable {
    let major: Int
    static func < (l: Version, r: Version) -> Bool { l.major < r.major }
}
print(Version(major: 1) < Version(major: 2))  // true

فرز نوع من Comparable

struct Score: Comparable {
    let points: Int
    static func < (l: Score, r: Score) -> Bool { l.points < r.points }
}
let sorted = [Score(points: 3), Score(points: 1), Score(points: 2)].sorted()
print(sorted.map { $0.points })  // [1, 2, 3]

احصلوا على min وmax مجانًا

struct Temp: Comparable {
    let c: Int
    static func < (l: Temp, r: Temp) -> Bool { l.c < r.c }
}
let temps = [Temp(c: 20), Temp(c: 5), Temp(c: 30)]
print(temps.min()!.c, temps.max()!.c)  // 5 30

الترتيب حسب عدة مفاتيح

حيلة مقارنة الصفوف

struct Person: Comparable {
    let last: String
    let first: String
    static func < (l: Person, r: Person) -> Bool {
        (l.last, l.first) < (r.last, r.first)
    }
}
let p = [Person(last: "Lee", first: "Bo"), Person(last: "Lee", first: "An")].sorted()
print(p.map { $0.first })  // ["An", "Bo"]

الفرز من دون Comparable

struct Item { let name: String; let qty: Int }
let items = [Item(name: "B", qty: 2), Item(name: "A", qty: 5)]
let byQty = items.sorted { $0.qty > $1.qty }
print(byQty.map { $0.name })  // ["A", "B"]

الفرز التنازلي

let nums = [3, 1, 4, 1, 5]
print(nums.sorted(by: >))         // [5, 4, 3, 1, 1]
print(nums.sorted().reversed())   // [5, 4, 3, 1, 1]

sorted مقارنةً بـ sort

var nums = [3, 1, 2]
nums.sort()
print(nums)  // [1, 2, 3]
let copy = [3, 1, 2].sorted()
print(copy)  // [1, 2, 3]

فرز مستقر بما يكفي

let words = ["bb", "a", "cc", "d"]
let byLen = words.sorted { $0.count < $1.count }
print(byLen)  // ["a", "d", "bb", "cc"]  -- "a" before "d", "bb" before "cc"

الفرز حسب مسار خاصية

struct Player { let name: String; let score: Int }
let players = [Player(name: "A", score: 30), Player(name: "B", score: 50)]
let ranked = players.sorted { $0.score > $1.score }
print(ranked.map { $0.name })  // ["B", "A"]

تحقق سريع

مراجعة