iOS. How to shift array in swift

Let's assume the problem: we have an array of elements, no matter what, numbers or rows or any other. It is necessary to move the array several positions to the left. For example:

source array [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

shifted array [3, 4, 5, 6, 7, 8, 9, 10, 1, 2]

We shift array left to 2 elements, so now third element with index 2 is become first with index 0.


Shifting with using for loop 

import UIKit
import Foundation

let numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
//needed result = [3, 4, 5, 6, 7, 8, 9, 10, 1, 2]

let neededNumber = 3
var firstPart = [Int]()
var secondPart = [Int]()
for number in numbers {
    if number == neededNumber || firstPart.count > 0 {
        firstPart.append(number)
    } else {
        secondPart.append(number)
    }
}

let result = firstPart + secondPart
// result = [3, 4, 5, 6, 7, 8, 9, 10, 1, 2]

Shifting with index, prefix and suffix methods

let numbersArray = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
//needed result = [3, 4, 5, 6, 7, 8, 9, 10, 1, 2]

let index = numbersArray.index(where: { $0 == 3 })
let prefix = numbersArray.prefix(upTo: index!)
// not include element at the end position
// prefix = [1, 2]

let suffix = numbersArray.suffix(from: index!)
// from specified postion to the end of array
// suffix = [3, 4, 5, 6, 7, 8, 9, 10]

let shiftingArray = suffix  + prefix
// shiftingArray = [3, 4, 5, 6, 7, 8, 9, 10, 1, 2]

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