Randomly generated security code with a prefix to set the length of their own

<?php
/* Auto-Generate security code with prefix to set length by itself */
$length = 10;
$result = Codingone ($length);
echo $result;
function Codingone ($num) {
/* judgment Generation rule */
$str _arr = Array (' 0 ', ' 1 ', ' 2 ', ' 3 ', ' 4 ', ' 5 ', ' 6 ', ' 7 ', ' 8 ', ' 9 ', ' A ', ' B ', ' C ', ' d ', ' e ', ' f ', ' g ', ' h ', ' I ', ' j ', ' K ', ' l ', ' m ', ' n ' , ' O ', ' P ', ' Q ', ' R ', ' s ', ' t ', ' u ', ' V ', ' w ', ' x ', ' y ', ' z ', ' A ', ' B ', ' C ', ' D ', ' E ', ' F ', ' G ', ' H ', ' I ', ' J ', ' K ', ' L ', ' M ', ' N ', ' o ', ' P ', ' Q ', ' R ', ' S ', ' T ', ' U ', ' V ', ' W ', ' X ', ' Y ', ' Z ');
$str _arr = Array (' A ', ' B ', ' C ', ' d ', ' e ', ' f ', ' g ', ' h ', ' I ', ' j ', ' K ', ' l ', ' m ', ' n ', ' o ', ' P ', ' Q ', ' R ', ' s ', ' t ', ' u ', ' V ', ' w ', ' x ' , ' y ', ' z ', ' A ', ' B ', ' C ', ' D ', ' E ', ' F ', ' G ', ' H ', ' I ', ' J ', ' K ', ' L ', ' M ', ' N ', ' O ', ' P ', ' Q ', ' R ', ' S ', ' T ', ' U ', ' V ', ' W ', ' X ', ' y ', ' Z ');
$str _arr = Array (' 0 ', ' 1 ', ' 2 ', ' 3 ', ' 4 ', ' 5 ', ' 6 ', ' 7 ', ' 8 ', ' 9 ');
$prefix = "Nono";
$rand _s = Array_rand ($str _arr, $num);
$code _s = ";
if (Is_array ($rand _s)) {
foreach ($rand _s as $v) {
$code _s. = $str _arr[$v];
}
Return $prefix. $code _s;
}else{
Return $prefix. $str _arr[' rand_s '];
}
}

?>

Randomly generated security code with a prefix to set the length of their own