Greek Social Security Number (SSN) Validation in Swift - Έλεγχος ορθότητας ΑΜΚΑ σε Swift

GreekSSNValidation.swift

//
//  GreekSSNValidation.swift
//
//  Created by Athanasios Papazoglou.
//  
//  Any feedback is appreciated 🤜🤛.
//  Also, you can reach me on Twitter (at)A_Ch_Papazoglou

import Foundation

extension String {
    var isValidGreekSSNNumber: Bool {
        if (self.range(of: "^\\d{11}$", options: .regularExpression) != nil) && (self != "00000000000") {
            var sum = 0
            let intArraySSN = self.compactMap({ Int(String($0)) })
            for i in stride(from: 1, through: self.count, by: 1) {
                var ithDigit = intArraySSN[i-1]
                if (i % 2 == 0) {
                    ithDigit *= 2
                    if (ithDigit > 9) {
                        ithDigit -= 9
                    }
                }
                sum += ithDigit
            }
            return sum % 10 == 0
        } else {
            return false
        }
    }
}