title: php remove duplicates from multidimensional array by value
body: <p>I would like to remove duplicates by value as you can see from the <code>list_title</code>. I know there are several questions and answers to this but their solution doesn't work for me.</p>
  
  <p>Here is what I've tried:</p>
  
  <pre><code>$uniqueArray = array_map("unserialize", array_unique(array_map("serialize", $notify)));
  </code></pre>
  
  <p>Result:</p>
  
  <pre><code>Array
  (
  [0] =&gt; Array
      (
          [list_id] =&gt; 86
          [list_reference] =&gt; 130948
          [list_title] =&gt; Offer:  apartment 2+kk 
          [list_city] =&gt; Prague
          [list_date] =&gt; 2017-03-03 11:20:35
          [list_status] =&gt; 0
          [list_creator] =&gt; Company A
          [list_price] =&gt; 30000
          [list_furniture] =&gt; ["1","0","0"]
          [list_accommodation] =&gt; flat
      )
  
  [1] =&gt; Array
      (
          [list_id] =&gt; 87
          [list_reference] =&gt; 130947
          [list_title] =&gt; Offer:  apartment 2+kk 
          [list_date] =&gt; 2017-03-03 11:20:35
          [list_status] =&gt; 0
          [list_creator] =&gt; Company B
          [list_price] =&gt; 30000
          [list_furniture] =&gt; ["1","0","0"]
          [list_accommodation] =&gt; flat
      )
  
  [2] =&gt; Array ...
  </code></pre>
  
  <p>Expected result should be one of those because of the title:</p>
  
  <pre><code>Array
  (
  [0] =&gt; Array
  (
      [list_id] =&gt; 86
      [list_reference] =&gt; 130948
      [list_title] =&gt; Offer:  apartment 2+kk 
      [list_city] =&gt; Prague
      [list_date] =&gt; 2017-03-03 11:20:35
      [list_status] =&gt; 0
      [list_creator] =&gt; Company A
      [list_price] =&gt; 30000
      [list_furniture] =&gt; ["1","0","0"]
      [list_accommodation] =&gt; flat
  )
  </code></pre>