<?php
// Use preg_split() function
$string = "123,456,78,000";
$str_arr = preg_split ("/\,/", $string);
print_r($str_arr);
// use of explode
$string = "123,46,78,000";
$str_arr = explode (",", $string);
print_r($str_arr);
?>
вы можете сделать это так и использовать опцию сортировки как
$values = array ("zercggj.co.uk", "lkjhg.org.au", "qqxze.org.au",
"bfhgj.co.uk", "sdfgh.org.uk");
echo "<br>input:<br>";
foreach ($values as $host) echo "$host<br>";
// create a suitable structure
foreach ($values as $host)
{
$split = explode('.', $host, 2);
$printable[$split[1]][] = $split[0];
}
// sort by domains
asort ($printable);
// output
echo "<br>sorted:<br>";
foreach ($printable as $domain => $hosts)
{
echo "domain: $domain<br>";
// sort hosts within the current domain
asort ($hosts);
// display them
foreach ($hosts as $host)
echo "--- $host<br>";
}