find the index item in an array

Question

Created Feb ’21

Replies 6

Boosts 0

Participants 4

Hello,

I want to check if the element 'Medic()' exists in my array.

`var array = [Medic(), AssaultSoldier(), Sniper()] `

Thank you all.

Answered by DTS Engineer in 661074022

Swift’s standard library includes a wealth of algorithms that you can reuse and thus make your code simpler and smaller. For example:

Code Block  class Soldier { }
class Medic: Soldier { }
class AssaultSoldier: Soldier { }
class Sniper: Soldier { }
let array = [Medic(), AssaultSoldier(), Sniper()]
let containsMedic = array.contains(where: { $0 is Medic })
print(containsMedic)        // true
let indexOfFirstMedic = array.firstIndex(where: { $0 is Medic })
print(indexOfFirstMedic)    // Optional(0)

The contains(where:) method returns true if the supplied closure return true for any item in the collection, while the firstIndex(where:) returns the index of that item.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@apple.com"

Boost

Answer 1

OOPer OP

Feb ’21

I want to check if the element 'Medic()' exists in my array.

It depends on the definition of Medic and other types in the array.

0

Answer 2

BChef001 OP

Feb ’21

These are Class !

0

Answer 3

OOPer OP

Feb ’21

These are Class !

Stating it as class is not the definition.

0

Answer 4

Claude31 OP

Feb ’21

I did the following small demo to show:

Code Block class Player {
    var name: String = "Player"
}
class Medic : Player {
    override init() {
        super.init()
        name = "Medic"
    }
}
class AssaultSoldier : Player {
    override init() {
        super.init()
        name = "AssaultSoldier"
    }
}
class Sniper : Player {
    override init() {
        super.init()
        name = "Sniper"
    }
}

then

Code Block     var array = [Medic(), AssaultSoldier(), Sniper()]
   let thereIsMedic = array.filter {$0 is Medic }.count > 0
   print(thereIsMedic)

And to get the position of Medic:

Code Block         for (pos, item) in array.enumerated() {
            if item is Medic {
                print("position of Medic is", pos)
                break
            }
        }

If that's what you're looking for, don't forget to close the thread

0

Answer 5

Claude31 OP

Feb ’21

You could also use map:

Code Block         let boolArray = array.map {$0 is Medic}
        let index = boolArray.firstIndex(of: true) ?? -1
        print("Medic at", index)

Or, in a more condensed form (here to find Sniper)

Code Block         let sniperIndex = array.map {$0 is Sniper}.firstIndex(of: true) ?? -1
        print("Sniper at", sniperIndex)

0

Answer 6

DTS Engineer OP

Apple

Feb ’21

Accepted Answer

Swift’s standard library includes a wealth of algorithms that you can reuse and thus make your code simpler and smaller. For example:

Code Block  class Soldier { }
class Medic: Soldier { }
class AssaultSoldier: Soldier { }
class Sniper: Soldier { }
let array = [Medic(), AssaultSoldier(), Sniper()]
let containsMedic = array.contains(where: { $0 is Medic })
print(containsMedic)        // true
let indexOfFirstMedic = array.firstIndex(where: { $0 is Medic })
print(indexOfFirstMedic)    // Optional(0)

The contains(where:) method returns true if the supplied closure return true for any item in the collection, while the firstIndex(where:) returns the index of that item.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@apple.com"

0