Random string

String+Extension.swift

extension String {
  
  static func randomString(length: Int) -> String {
    let letters : NSString = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    let len = UInt32(letters.length)
    
    var randomString = ""
    
    for _ in 0 ..< length {
      let rand = arc4random_uniform(len)
      var nextChar = letters.character(at: Int(rand))
      randomString += NSString(characters: &nextChar, length: 1) as String
    }
    return randomString
  }
  
  func validEmail() -> Bool {
    let emailRegex = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}"
    let emailText = NSPredicate(format:"SELF MATCHES [c]%@",emailRegex)
    return (emailText.evaluate(with: self))
  }
  
}