find the file name extension of a file - PHP

<?php

function getExt($filenames) {

if (!is_array($filenames)) {
$filenames = (array) $filenames;
}

foreach ($filenames as $key => $value) {
$output[$value] = end(explode('.', $value));
}

return $output;

}
$array=array('a.txt','b.doc','c.xml');
print_r(getExt($array));
?>

Array
(
    [a.txt] => txt
    [b.doc] => doc
    [c.xml] => xml
)