Filtering array of custom objects with NSPredicate via binding

Question

class MyClass {
    var result: Bool

    init(result: Bool) {
        self.result = result
     } 
}

I have an array( [MyClass] ) in my ArrayController connected via binding and I need to filter this array by property result .

For example half of these objects have result as false, I only want to display these items which have result == true , but it must be done with NSPredicate and I don't have any clue how to make this predicate, any ideas?

To make it clear, I'm required to use filterPredicate variable of NSArrayController to filter this array.

Answer 1

First of all, your class MyClassmust conform to NSObject, this turns the declaration into,

class MyClass: NSObject {
var result: Bool
init(result: Bool) {
    self.result = result
 } 
}

then you can apply the NSPredicate as,

let bPredicate: NSPredicate = NSPredicate(format: "result contains[cd]       %@", true)
let searchArray = yourArray.filtered(using: bPredicate) as NSArray

Answer 2

Ok, I solved problem by myself. Here is the code

arrayController.filterPredicate = NSPredicate { object, _ in
    (object as? MyClass)?.result
}

for dynamic var

dynamic var predicate: NSPredicate? = {
    return NSPredicate { object, _ in
        (object as? MyClass)?.result
    }
}()

Answer 3

用户筛选器代替NSPredicate

'let filteredArray = yourArray.filter({$0.result == true})'