Best way to generate a 2 char alphanumeric string?

Question

Hi, what is the fastest way to generate a random two long alphanumeric character?

Thanks, Max

Answer 1

How about

$az = range('a', 'z');
$r = array_rand($az, 2);
$str = $az[$r[0]] . $az[$r[1]];

Answer 2

This would do the job beautifully:

substr(md5(uniqid(microtime(true),true)),0,2);

This technique is used quite often for alphanumeric password salts in databases.

Answer 3

Based on Jani's answer:

join('', array_rand(array_merge(range('a', 'z'), range('0', '9')), 2))

Answer 4

how about this?

base_convert(rand(0,35), 10, 36) . base_convert(rand(0,35), 10, 36)