title: What do _._1 and _++_ mean in Scala (two separate operations)?
body: <p>My interpretation of <code>_._1</code> is: </p>
  
  <p><code>_</code> = wildcard parameter
  <code>_1</code> = first parameter in method parameter list
  But when used together with <code>.</code> what does it signify?</p>
  
  <p>This is how its used : </p>
  
  <pre><code>.toList.sortWith(_._1 &lt; _._1)
  </code></pre>
  
  <p>For this statement: </p>
  
  <pre><code>_++_
  </code></pre>
  
  <p>I'm lost. Is it concatenation two wildcard parameters somehow? 
  This is how its used: </p>
  
  <pre><code>.reduce(_++_)
  </code></pre>
  
  <p>I would be particularly interested if they above code could be made more verbose and remove any implicits, just so I can understand it better?</p>