我有这个PHP代码如何让它生成从1到16的随机长度

I have this php code how can i make it generate random from 1 to 10

$seed = str_split('aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ123456789');
$rand = array_rand($seed, 16);
$convert = array_map(function($n){
    global $seed;
    return $seed[$n];
},$rand);

$var1 = implode('',$convert);

so need this one to show random not 16 like its there but random length from 1 to 16 each time user comes.

Here's a code snippet without using map

function generateRandString($length = 10) {
    $chars = 'abcdefghijklmnopqrstuvwxyz0123456789';
    $charsLength = strlen($chars);
    $randomString = '';
    for ($i = 0; $i < $length; $i++) {
        $randomString .= $chars[rand(0, $charsLength - 1)];
    }
    return $randomString;
}

You can shuffle() the array and use array_slice() to get n number of items from the array.
Including a rand() inside the array slice means it returns a random length between 1 and 10 characters.

$seed = str_split('aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ123456789');

shuffle($seed);
echo implode("", array_slice($seed,0,rand(1,10)));

https://3v4l.org/RX9XO

Easiest way to achieve what you want without rewriting all your code is to replace:

$rand = array_rand($seed, 16);

with

$rand = array(array_rand($seed, mt_rand(1,10)));

That will simply pass a different length parameter to array_rand() on each run