Question

我有一个单元格模型

struct BeerCellModel: Hashable {

    var beer: Beer

    static func == (lhs: BeerCellModel, rhs: BeerCellModel) -> Bool {
        return lhs.beer.id == rhs.beer.id
    }

    var hashValue: Int {
        return self.beer.id
    }
}

AND

public struct Beer {
    public var abv: String
    public var ibu: String
    public var id: Int
    public var name: String
    public var style: String
    public var ounces: Int
}

现在我具有上述单元格模型的数组名称' items = [BeerCellModel] '，并且我正在使用参数style

过滤数组

let value = ["tuborg", "budwiser", "bira"]
let query = value.map { "SELF.beer.style CONTAINS[cd] \($0)" }.joined(separator: " || ")
let predicate = NSPredicate(format: query)
let results = self.items.filter { predicate.evaluate(with: $0) }

但是我遇到了运行时崩溃

2018-08-08 00：38：01.787170 + 0530 BeerCrafts [3388：401950] *** 由于未捕获的异常“ NSUnknownKeyException”而终止应用程序，原因：'[<_SwiftValue 0x60400064dce0> valueForUndefinedKey：]：此类别不符合密钥啤酒的密钥值编码要求。'

数组或谓词有什么问题？

更新：添加Beer

的JSON响应

  {
    "abv": "0.08",
    "ibu": "35",
    "id": 11,
    "name": "Monks Blood",
    "style": "Belgian Dark Ale",
    "ounces": 12
  },
  {
    "abv": "0.07",
    "ibu": "65",
    "id": 10,
    "name": "Brew Free! or Die IPA",
    "style": "American IPA",
    "ounces": 12
  },
  {
    "abv": "0.04",
    "ibu": "17",
    "id": 9,
    "name": "Hell or High Watermelon Wheat",
    "style": "Fruit / Vegetable Beer",
    "ounces": 12
  }

Answer 1

此时，无需处理arr = [true, false, false, true, false]，Chai.expect(_.filter(arr, item => item == true)).to.have.length(2)方法足以满足您的情况，例如：

NSPredicate

filter是let filtered = items.filter { value.contains($0.beer.style) }的数组，其中应包含其filtered是BeerCellModel数组元素之一的对象。

Answer 2

您可以尝试

let value = ["tuborg", "budwiser", "bira"]
let query = value.map { "self CONTAINS[cd] '\($0)'" }.joined(separator: " || ")
let predicate = NSPredicate(format: query)
let results = self.items.filter { predicate.evaluate(with: $0.beer.style) }

Answer 3

看起来您正在尝试映射String数组，而不是BeerCellModel结构数组。

使用NSPredicate的iOS Swift过滤器数组在运行时崩溃

3 个答案: