title: Efficiently repeat a character/string n times in Scala
body: <p>I would like to do the following more efficiently:</p>
  
  <pre><code>def repeatChar(char:Char, n: Int) = List.fill(n)(char).mkString
  def repeatString(char:String, n: Int) = List.fill(n)(char).mkString
  
  repeatChar('a',3)     // res0: String = aaa
  repeatString("abc",3) // res0: String = abcabcabc
  </code></pre>