Arrays Swift 3排序jsonArray

请告诉我如何在“bonusCardsArray”中根据“currentPoints”值对多个“BonusCard”数组进行排序（降序、升序）

要就地排序（按w.r.t.升序排列到

currentPoints

属性），请使用

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您应该编写以下代码

• 下降
  已排序（{$0.currentPoints>$1.currentPoints}）

• 为了提升
  已排序（{$0.currentPoints<$1.currentPoints}）

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非常感谢，朋友们。无法想象一艘邮轮能做这么多事情：-）

//Array to sort according to "currentPoints" 
var bonusCardsArray = [BonusCard]()

//basis class
class BonusCard {

  var companyName             : String
  var bonusCardDescription    : String
  var currentPoints           : Int
  var bonusCardType           : Int


  init(companyName: String, bonusCardDescription: String,    
  currentPoints: Int, bonusCardType: Int) {

      self.companyName = companyName
      self.bonusCardDescription = bonusCardDescription
      self.currentPoints = currentPoints
      self.bonusCardType = bonusCardType
  }
}

bonusCardsArray.sort { $0.currentPoints < $1.currentPoints }

let sortedfBonusCardsArray = bonusCardsArray
    .sorted { $0.currentPoints < $1.currentPoints }