Random string with pattern

[rufy]

Is there a way to generate a random string with a particular pattern? e.g. ar5-Edg-2ah

[shogunkaramazov]

@rufy You should create a random string generator in this case like this:

class RandomString {
  // 1
  private let parts: Int
  private var strings: [String] = []
  
  private enum CharacterType: Int {
    case digit, upper, lower
  }
  
  // 2
  init(parts: Int = Int.random(in: 1...10)) {
    self.parts = parts
    create()
  }
  
  // 3
  private func create() {
    for _ in 1...parts {
      let part = Int.random(in: 1...10)
      let string = createString(part)
      strings.append(string)
    }
  }
  
  // 4
  private func createString(_ part: Int) -> String {
    var string = ""
    for _ in 1...part {
      let character = createCharacter()
      string.append(character)
    }
    return string
  }
  
  // 5
  private func createCharacter() -> Character {
    let type = Int.random(in: 0...2)
    let characterType = CharacterType(rawValue: type)!
    switch characterType {
      case .digit: return getCharacter(48, 57)
      case .upper: return getCharacter(65, 90)
      case .lower: return getCharacter(97, 122)
    }
  }
  
  // 6
  private func getCharacter(_ lower: Int, _ upper: Int) -> Character {
    let value = Int.random(in: lower...upper)
    let scalar = Unicode.Scalar(value)!
    return Character(scalar)
  }
  
  // 7
  func format(with separator: String = "-") -> String {
    strings.joined(separator: separator)
  }
}

There is quite a lot going on over here, so breaking it into steps:

1. Define the number of substrings and the type of characters in the final string.
2. Use random numbers to generate the number of substrings in the final string.
3. Use random numbers to generate the number of characters in the substrings and append the substrings to the final string.
4. Create the substrings by appending their characters.
5. Use random numbers to determine the type of the characters in the substrings and create the characters in the substrings.
6. Get the specific character from its corresponding Unicode scalar.
7. Get the final string by joining its substrings.

This is how you use the random string generator:

let randomString = RandomString()
let string = randomString.format()
print(string)

Please let me know if you have any questions or issues about the whole thing when you get a chance. Thank you!