在 Swift 中按特定顺序对数组进行排序

Question

我想在 swiftUI 中按特定顺序对数组进行排序

let list = ["A","B","A1","C","B1","AA"]

我试过了：

let sortedList = list.sorted{ $0.localizedStandardCompare($1) == .orderedAscending }
// Output : sortedList = ["A","A1","AA","B","B1","C"]

还有

let sortedList = list.sorted{ $0.parcoursNom < $1.parcoursNom }
// Output : sortedList = ["A","A1","AA","B","B1","C"]

预期：

sortedList = ["A","AA","B","C","A1","B1"]

如果以一个数字结束，那么在最后

Answer 1

你需要一个自定义的排序函数

let sortedList = list.sorted {
    switch ($0.last!.isNumber, $1.last!.isNumber) {
    case (true, false):
        return false
    case (false, true):
        return true
    default:
        return $0 < $1
    }
}

如果您需要处理可能的空字符串，请为此添加两个case，我们可以避免强制解包

let sortedList = list.sorted {
    switch ($0.last?.isNumber, $1.last?.isNumber) {
    case (true, false):
        return false
    case (false, true):
        return true
    case (nil, _):
        return false
    case (_, nil):
        return true
    default:
        return $0 < $1
    }
}

Answer 2

有时，尤其是在对元组进行排序时，能够“使布尔值具有可比性”会很有帮助。这样，您可以使用元组定位来赋予排序优先级。

["A","B","A1","C","B1","AA"].sorted {
  let comparables = { (string: String) in
    ( (string.last?.isNumber ?? false).comparable,
      string
    )
  }

  return comparables($0) < comparables($1)
}

public extension Bool {
  /// A way to compare `Bool`s.
  ///
  /// Note: `false` is "less than" `true`.
  enum Comparable: CaseIterable, Swift.Comparable {
    case `false`, `true`
  }

  /// Make a `Bool` `Comparable`, with `false` being "less than" `true`.
  var comparable: Comparable { .init(booleanLiteral: self) }
}

extension Bool.Comparable: ExpressibleByBooleanLiteral {
  public init(booleanLiteral value: Bool) {
    self = value ? .true : .false
  }
}