ios - 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。

我有一个有点乱的数据源，我用它来填充 UITableView。数据源是一个结构数组。该结构定义如下:

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 Controller 中，我持有一个结构数组，其中包含表的所有数据。

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()
}

我想做的是根据“名称”字段过滤 exercises 数组，并填充新的数据源 filtered_exercises 以填充 TableView 。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将其显示在表格 View 中。问题是我需要保留结构，因为那里包含的数据被传递到其他 View Controller 。

那么，如何过滤结构数组？

谢谢!

Answer 1

如果您不坚持使用 NSPredicate(因为您没有使用 NSFetchRequest，所以没有理由这样做，...)，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Water Polo、Volleyball、Golf。