if you have a numer like 0310, don't use this code:
$number = '0310';
$number = ltrim( $number, "\0x30" );
echo $number;
output: 10
for a correct output use:
$number = '0310';
$number = ltrim( $number, "0" );
echo $number;
output: 310
the "\0x30" works only with the first 32 ascii characters