$re = '/:\D{8}\d{2}/m';
$str = '1:nlcbjduy14 <- I want regex to find this one
2:Peoples123 <- I don\'t want regex to find this one, as it has 3 digits.
3:sqourzyr17 <- I want regex to find this one
4:rdmaszgr94 <- I want regex to find this one
5:tnwiudic22 <- I want regex to find this one
6:zfcxmkrs21 <- I want regex to find this one
7:xrwhsgno55 <- I want regex to find this one
8:modtwtrr06 <- I want regex to find this one
9:People123 <- I don\'t want regex to find this one, as it is isn\'t 10 chars long and it consists of 3 digits.
10:aetmyqqh52 <- I want regex to find this one
11:Howtocodelikeapro12 <- I don\'t want regex to find this one, as it is isn\'t 10 chars long
12:netphvib58 <- I want regex to find this one
13:uwyiqhoj29 <- I want regex to find this one
14:RegexJustiIsntDoingItForMe
15:qyeiaecj27 <- I want regex to find this one
16:buttercake <- I don\'t want regex to find this one, as it doesn\'t end with 2 digits.
17:bcyiyjdm23 <- I want regex to find this one
18:Differings <- I don\'t want regex to find this one, as it doesn\'t end with 2 digits.';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php