WordPress scripts for 3 column layout that checks to see if the element is the middle in a three column layout or a new row. Use it to clear floats and add styles such as left and right margins for the middle column.

is_middle_column.php

// Custom function to check if column is middle column
// of a three column layout based on the index
function is_middle_column($index)
{
	$isMiddleColumn = false;
	$postIndex = $index;
	
	if (($postIndex - 1) % 3 == 0)
	{
		$isMiddleColumn = true;
	}	
	
	return $isMiddleColumn;
}

is_new_row.php

function is_new_row($index)
{
	$isNewColumn = false;
	$postIndex = $index;

	if (($postIndex > 0) && ($postIndex % 3 == 0))
	{
		$isNewColumn = true;	
	}
	
	return $isNewColumn;
}