title: Remove Array Elements Without Array_Unique
body: <p>Trying to remove duplicate array elements without using array_unique. I am trying to use the array_flip method but that doesn't seem to be working for me. The Code that I have so far is:</p>
  
  <pre><code>$arr = array(
     'a' =&gt; "one",
     'b' =&gt; "two",
     'c' =&gt; "three",
     'd' =&gt; "two",
     'e' =&gt; "four",
     'f' =&gt; "five",
     'g' =&gt; "three",
     'h' =&gt; "two"
  );
  
  function removeDuplicates($arr) {
  
  
  $arr = array_flip($arr);
  $arr = array_flip($arr);
  
  }
  print_r(removeDuplicates($arr));
  </code></pre>
  
  <p>The output that I am trying to get ultimately is:</p>
  
  <pre><code>  [a] =&gt; one
      [e] =&gt; four
      [f] =&gt; five
  </code></pre>
  
  <p>This is just purely for educational purposes as I am trying to find different ways to do it. Any help is great appreciated. </p>