Split Strings

My:
object Kata {
def solution(str:String):List[String]=
  {
    if(str.nonEmpty)
        str.split("(?<=\\G..)").toList.map(x=>{
    if(x.length ==1)
         x+"_"
    else x
  })
    else
      List()
  }
}

Other:
object Kata {

  def solution(s: String): List[String] = {
    s.grouped(2).map(_.padTo(2, '_')).toList
  }
}