function randStr($length=4,$type="1"){
$array = array(
'1' => '0123456789',
'2' => 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
'3' => '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ',
);
$string = $array[$type];
$count = strlen($string)-1;
$rand = '';
for ($i = 0; $i < $length; $i++) {
$rand .= $string[mt_rand(0, $count)];
}
return $rand;
}
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