Swift：使用 UISearchController/Predicates 过滤结构数组

Question

想知道是否有人可以帮助我在 Swift 中使用谓词进行过滤。

我有一个有点凌乱的数据源，用于填充 UITableView。数据源是一个结构数组。结构体定义如下：

struct Exercises {
    let category: String
    let name : String
    let x_seed: [Double]
    let y_seed: [Double]
    let hasMult: Bool
}

现在在我的 tableview 控制器中，我持有一个包含表的所有数据的结构数组。

class MainTableViewController: UITableViewController, UISearchResultsUpdating {


var exercises = [Exercises]()
var filtered_exercises = [Exercises]()
var resultSearchController = UISearchController()

override func viewDidLoad() {
    super.viewDidLoad()

    // MARK: - Table view data source
    self.exercises = [
        Exercises(category:"Sports", name:"Bowling", x_seed:[125,155,185], y_seed:[3.00, 3.73, 4.43], hasMult:false),
        Exercises(category:"Sports", name:"Water Polo", x_seed:[125,155,185], y_seed:[10.00, 12.40,14.80], hasMult:false),
        Exercises(category:"Sports", name:"Handball", x_seed:[125,155,185], y_seed:[12.00, 14.87, 17.77], hasMult:false),
        Exercises(category:"Sports", name:"Dancing", x_seed:[125,155,185], y_seed:[3.00, 3.73, 4.43], hasMult:true),
        Exercises(category:"Sports", name:"Frisbee", x_seed:[125,155,185], y_seed:[3.00, 3.73, 4.43], hasMult:false),
        Exercises(category:"Sports", name:"Volleyball", x_seed:[125,155,185], y_seed:[3.00, 3.73, 4.43], hasMult:false),
        Exercises(category:"Sports", name:"Archery", x_seed:[125,155,185], y_seed:[3.50, 4.33, 5.17], hasMult:false),
        Exercises(category:"Sports", name:"Golf", x_seed:[125,155,185], y_seed:[3.50, 4.33, 5.17], hasMult:true)]

    self.resultSearchController = ({
        let controller = UISearchController(searchResultsController: nil)
        controller.searchResultsUpdater = self
        controller.dimsBackgroundDuringPresentation = false
        controller.searchBar.sizeToFit()

        self.tableView.tableHeaderView = controller.searchBar

        return controller
    })()

    self.tableView.reloadData()
}

我想要做的是根据“名称”字段过滤练习数组，并填充一个新的数据源filtered_exercises 以填充表视图。我不确定在这种情况下如何使用谓词。

// Search functionality 
func updateSearchResultsForSearchController(searchController: UISearchController)
{
    filtered_exercises.removeAll(keepCapacity: false)

    let searchPredicate = NSPredicate(format: "SELF CONTAINS[c] %@", searchController.searchBar.text!)
    // ??????????????

    self.tableView.reloadData()
}

我知道我可以读取字符串数组中的所有名称并轻松地在 tableview 中显示它。问题是我需要保留结构，因为其中包含的数据被传递到其他视图控制器。

那么，如何过滤结构数组？

谢谢！

Answer 1

如果您不坚持NSPredicate（因为您没有使用，所以看不出您应该坚持的理由NSFetchRequest，...），这是代码：

struct Exercises {
  let category: String
  let name : String
  let x_seed: [Double]
  let y_seed: [Double]
  let hasMult: Bool
}

let exercises = [
  Exercises(category:"Sports", name:"Bowling", x_seed:[125,155,185], y_seed:[3.00, 3.73, 4.43], hasMult:false),
  Exercises(category:"Sports", name:"Water Polo", x_seed:[125,155,185], y_seed:[10.00, 12.40,14.80], hasMult:false),
  Exercises(category:"Sports", name:"Handball", x_seed:[125,155,185], y_seed:[12.00, 14.87, 17.77], hasMult:false),
  Exercises(category:"Sports", name:"Dancing", x_seed:[125,155,185], y_seed:[3.00, 3.73, 4.43], hasMult:true),
  Exercises(category:"Sports", name:"Frisbee", x_seed:[125,155,185], y_seed:[3.00, 3.73, 4.43], hasMult:false),
  Exercises(category:"Sports", name:"Volleyball", x_seed:[125,155,185], y_seed:[3.00, 3.73, 4.43], hasMult:false),
  Exercises(category:"Sports", name:"Archery", x_seed:[125,155,185], y_seed:[3.50, 4.33, 5.17], hasMult:false),
  Exercises(category:"Sports", name:"Golf", x_seed:[125,155,185], y_seed:[3.50, 4.33, 5.17], hasMult:true)
]

let options = NSStringCompareOptions.CaseInsensitiveSearch | NSStringCompareOptions.DiacriticInsensitiveSearch

// Filter exercises by name (case and diacritic insensitive)
let filteredExercises = exercises.filter {
  $0.name.rangeOfString("Ol", options: options) != nil
}

let filteredExerciseNames = ", ".join(filteredExercises.map({ $0.name }))
println(filteredExerciseNames)

它打印水球、排球、高尔夫球。