Sum of two index in array & its index

Code

func getIndexFromArray(_ arr: [Int],_ target: Int) -> String {
    var dic = [Int:Int]()
    var output = ""
    for i in 0 ..< arr.count {
        dic[arr[i]] = i
        let val = target - arr[i]
        let final = dic[val]
        if final != nil {
            output = output + "\n" + "\(i),\(final ?? 0)"
        }
    }
    return output
}

Example

// Example usage
let arr = [2,6,9,1,7,4,11]
let target = 10
print(getIndexFromArray(arr, target))

Output

3,2
5,1