How to search in a array of model objects based on the value [duplicate]

Question

This is an example of my model object

class Person: NSObject, NSCoding {
    let id: Int
    let name: String
    let age: Int

    init(id: Int, name: String, age: Int) {
        self.id = id
        self.name = name
        self.age = age
    }
    required init(coder decoder: NSCoder) {
        self.id = decoder.decodeInteger(forKey: "id")
        self.name = decoder.decodeObject(forKey: "name") as? String ?? ""
        self.age = decoder.decodeInteger(forKey: "age")
    }
    func encode(with coder: NSCoder) {
        coder.encode(id, forKey: "id")
        coder.encode(name, forKey: "name")
        coder.encode(age, forKey: "age")
    }
}

I am creating some person objects and adding to an array

    let newPerson1 = Person(id:"101", name: "Joe1", age: 10)
    let newPerson2 = Person(id:"102", name: "Joe2", age: 11)
    var people = [Person]()
    people.append(newPerson1)
    people.append(newPerson2)

    //saving to file
    let documentsDirectory =  try! FileManager().url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
    let listOfTasksURL = documentsDirectory.appendingPathComponent("listOfTasks.plist")
    NSKeyedArchiver.archiveRootObject(people, toFile: listOfTasksURL.path)

    // retrieving from the file
    var peopleArray = [Person]()
    if let tempArr: [Person] = NSKeyedUnarchiver.unarchiveObject(withFile: listOfTasksURL.path) as? [Person] {
        peopleArray = tempArr
    }
    print(peopleArray)

    let data = peopleArray[0]
    print(data.id)

I am getting the values succesfully. I want to search for the 'Person' object with id '101' and delete it from the array and save the modified array back to file. I want to return a flag if the item is not in the list and add the item to list if its not there. How can i accomplish this.

Thank you for any help.

Nirav D · Accepted Answer · 2017-06-23 12:22:13Z

1

You can use index(where:) to get the index of that object and after getting index you can easily remove that object from array.

func deleteObject(with id: Int) -> Bool
    if let index = people.index(where: { $0.id == id }) {
        people.remove(at: index)
        return true
    }
    return false
}

//Now use this method like this
if deleteObject(with: 101)  {
    //object is successfully deleted now save data in array
    let documentsDirectory =  try! FileManager().url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
    let listOfTasksURL = documentsDirectory.appendingPathComponent("listOfTasks.plist")
    NSKeyedArchiver.archiveRootObject(people, toFile: listOfTasksURL.path)
}
else {
    //object is not present in array add new object
}

edited Jun 23, 2017 at 12:22

answered Jun 23, 2017 at 11:53

Nirav D

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7 Comments

proCoder Over a year ago

Thanks, is i am using the correct way to save the array to the file ?

Nirav D Over a year ago

@proCoder It looks ok, Are you facing any issue with it?

proCoder Over a year ago

Yes its working nice , but how can i save the modified array back to file. I want to return a flag if the item is not in the list and add the item if its not there.

proCoder Over a year ago

Please see my updated question. Thank you

Nirav D Over a year ago

@proCoder Check the edited answer :)

|

KKRocks · Accepted Answer · 2017-06-23 11:55:03Z

1

Try this :

if let expectedIndex = people.index(where: { $0.id == 101 }) {
    people.remove(at: expectedIndex)
}

More: Trailing Closure

answered Jun 23, 2017 at 11:55

KKRocks

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