- mt_rand: documentation ( source)
- array_merge: documentation ( source)
- range: documentation ( source)
- str_pad: documentation ( source)
<?php
function CreateA6DigitUserID()
{
$az = array_merge(range('A','Z'), range('a','z'));
$one = $az[mt_rand(0,count($az)-1)];
$two = $az[mt_rand(0,count($az)-1)];
$digits = str_pad(mt_rand(0,9999), 4, "0", STR_PAD_LEFT);
return $one.$two.$digits;
}
echo CreateA6DigitUserID();