title: Add new element to list
body: <p>I was trying to add a new element into a list as follow:</p>
  
  <pre><code>iex(8)&gt; l = [3,5,7,7,8] ++ 3
  [3, 5, 7, 7, 8 | 3]
  iex(9)&gt; l
  [3, 5, 7, 7, 8 | 3]
  </code></pre>
  
  <p>Why did I get on the 5th position like</p>
  
  <pre><code>8 | 3
  </code></pre>
  
  <p>What it does mean?<br>
  And how can I add new element to the list?</p>
  
  <p>--------<strong>Update</strong>--------<br>
  I try to loop the list as follow:</p>
  
  <pre><code>iex(2)&gt; l = [1,2] ++ 3
  [1, 2 | 3]
  iex(3)&gt; Enum.each(l, fn(x) -&gt; IO.puts(x) end)
  1
  2
  ** (FunctionClauseError) no function clause matching in Enum."-each/2-lists^foreach/1-0-"/2
      (elixir) lib/enum.ex:604: Enum."-each/2-lists^foreach/1-0-"(#Function&lt;6.54118792/1 in :erl_eval.expr/5&gt;, 3)
      (elixir) lib/enum.ex:604: Enum.each/2
  </code></pre>
  
  <p>Since the pointer of the number 2 is not pointing to a list, rather to value 3, how can I loop the list?</p>