title: Scala mkString except the last one
body: <p>I would like to do the following in scala:</p>
  
  <pre><code>val l = List("An apple", "a pear", "a grapefruit", "some bread")
  ... some one-line simple function ...
  "An apple, a pear, a grapefruit and some bread"
  </code></pre>
  
  <p>What would be the shortest way to write it that way?</p>
  
  <p>My best attempt so far is:</p>
  
  <pre><code>def makeEnumeration(l: List[String]): String = {
    var s = ""
    var size = l.length
    for(i &lt;- 0 until size) {
      if(i &gt; 0) {
        if(i != size - 1) { s += ", "
        } else s += " and "
      }
      s += l(i)
    }
    s
  }
  </code></pre>
  
  <p>But it is quite cumbersome. Any idea?</p>