Question

How to find duplicate elements in an array with Swift

Answer 1

import Foundation

func findDuplicates(in array: [Int]) -> [Int] {
    var seen = Set<Int>()
    var duplicates = [Int]()

    for item in array {
        if !seen.insert(item).inserted {
            duplicates.append(item)
        }
    }

    return duplicates
}

let arr = [1, 2, 3, 2, 2, 4, 4, 4, 4, 3, 5, 6, 3]

let duplicates = findDuplicates(in: arr)

print("Duplicates: \(duplicates)")




/*
run:
   
Duplicates: [2, 2, 4, 4, 4, 3, 3]

*/

 

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