Swift NSPredicate with Array

NSPredicate is a class that specify data format. It shows how data to be fetched. If you are familiar with SQL language, you will find it easy to use it. The example below show how it is used in normal array.

First create Person model to use with Array

class Person : NSObject {

    let name : String

    let age : Int

    let salary : Double

    

    init(name:String, age:Int, salary:Double){

        self.name = name

        self.age = age

        self.salary = salary

    }

}

Then create an array of person with some initialize data

let arrPeople = [

            Person(name: "Mary", age: 21, salary: 100),

            Person(name: "Tina", age: 22, salary: 200),

            Person(name: "Kin", age: 23, salary: 300),

            Person(name: "Pal", age: 24, salary: 400),

            Person(name: "Qusa", age: 25, salary: 500)

        ]

Create 3 predicate consisting of Name, Age and Salary

let namePredicate =  NSPredicate(format: "name == \"Qusa\" ", argumentArray: nil)

let agePredicate = NSPredicate(format: "age == 22", argumentArray: nil)

let salaryPredicate = NSPredicate(format: "salary == 300", argumentArray: nil)

Then fetch the result from the 3 predicates using function Filtered

let arrName = (arrPeople as NSArray).filtered(using: namePredicate) as! [Person]

let arrAge = (arrPeople as NSArray).filtered(using: agePredicate) as! [Person]

let arrSalary = (arrPeople as NSArray).filtered(using: salaryPredicate) as! [Person]

Finally print to see the result

print("Predicate name result : \(arrName.first?.name ?? "" ) ")

print("Predicate age result : \(arrAge.first?.name ?? "" )")

print("Predicate salary result : \(arrSalary.first?.name ?? "" )")

Congratulation, you just know how to use NSPredicate with Array. Here is the full source code.