如何返回布爾值？

Question

所以我有一個類的方法isApplicableToList(list: [ShoppingItem]) -> Bool。如果可以根據提供的產品ID列表應用折扣（即，產品必須與報價匹配）並且產品ID是901和902，則應該返回true。

我已經嘗試過但不確定是否完成正確或者如果有更好的方法。

在此先感謝！

class HalfPriceOffer :Offer { 

    init(){ 
     super.init(name: "Half Price on Wine") 
     applicableProductIds = [901,902]; 
    } 

    override func isApplicableToList(list: [ShoppingItem]) -> Bool { 
     //should return true if a dicount can be applied based on the supplied list of product ids (i.e. a product must be matched to an offer) 

     if true == 901 { 
      return true 
     } 
     if true == 902 { 
      return true 
     } 

     else { 

      return false 

     } 
    } 
} 

ShoppingItem

class ShoppingItem { 

    var name :String 
    var priceInPence :Int 
    var productId :Int 

    init(name:String, price:Int, productId:Int){ 
     self.name = name 
     self.priceInPence = price 
     self.productId = productId 
    } 
} 

Answer 1

遍歷列表和測試的項目，如果該項目的productId是使用contains方法的applicableProductIds名單。如果沒有找到，請返回false。

override func isApplicableToList(list: [ShoppingItem]) -> Bool { 
    //should return true if a dicount can be applied based on the supplied list of product ids (i.e. a product must be matched to an offer) 

    for item in list { 
     if applicableProductIds.contains(item.productId) { 
      return true 
     } 
    } 

    // didn't find one  
    return false 
}