Manipulating every Nth item in a <% control %> loop

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16 July 2009 | Aram Balakjian | DataObjects, Templates | Supports v2.4, v2.3

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Often you will want to manipulate every nth item inside a <% control %> loop. For example say you had a gallery and you wanted every 3rd image to start on a new line, you need to be able to test each item from the template to see if it is divisible by 3 and should therefore have the clear CSS class added to it.

Using iteratorPos % we can very easily achieve this. First we need to add the test function to the object we will be iterating through, so for example if you are iterating through a number of ImageItem DataObjects, we would add this function to our ImageItem class:

public function IsThird(){	
	return ($this->iteratorPos % 3) == 0;
}

 

The % operator calculates the modulous or Remainder after dividing by the number that follows it (in this case 3). If there is a remainder then we know that the item is not divisible by 3 and so should not be cleared, but if the modulous is equal to 0 then we know it is divisible by 3 and should therefore clear a new line.

We can now use <% if IsThird %> to clear the third image in our template <% control %> loop like so:

<% control ImageItems %> 
     <li <% if IsThird %>class="clear"<% end_if %> >  
          Image
     </li>
<% end_control %>