title: Codeigniter: Include actual input value from validation error message
body: <p>Good day!</p>
  
  <p>Fast newbie question.</p>
  
  <p>I have this validation from controller:</p>
  
  <pre><code>$this-&gt;form_validation-&gt;set_rules("item_name", "Item Name", "trim|xss_clean|max_length[100]|required|is_unique[tbl_item.item_name]");
  // UPDATE: as suggested by Asad Khan and NARGIS PARWEEN, 
  // I changed this:
  // $this-&gt;form_validation-&gt;set_message("is_unique", "This %s already exists.");
  // into this:
  $this-&gt;form_validation-&gt;set_message("is_unique", "This {field} already exists.");
  
  // prints "This Item Code already exists" when validation fails.
  </code></pre>
  
  <p><strong>Question:</strong> How will I replace the <code>'%s'</code> into the actual <code>input value</code>? The result would be something like "<em>ITEM-01 already exists.</em>"</p>
  
  <p>Thanks in advance guys!</p>