How can the use of array_merge and array_unique in PHP help prevent data duplication when populating tables in Smarty templates?

When populating tables in Smarty templates, data duplication can occur if the same data is fetched multiple times from different sources. To prevent this, we can use `array_merge` to combine the data arrays and `array_unique` to remove any duplicate entries before passing the final array to the Smarty template.

// Fetch data from different sources
$data1 = fetchDataFromSource1();
$data2 = fetchDataFromSource2();

// Merge the data arrays and remove duplicates
$mergedData = array_unique(array_merge($data1, $data2));

// Assign the merged data to the Smarty template
$smarty->assign('tableData', $mergedData);