Is every letter in the alphabet in a string at least once?

Question

Was wondering if there was a more efficient way to detect if a string contains every letter in the alphabet one or more times using regex?

I appreciate any suggestions

$str = str_split(strtolower('We promptly judged antique ivory buckles for the next prize'));

$az = str_split('abcdefghijklmnopqrstuvwxyz');

$count = 0;
foreach($az as $alph) {
    foreach($str as $z) {
        if($alph == $z) {
           $count++;
            break;
        }
    }
}

Answer 1

Just use array_diff:

count(array_diff($az, $str)) > 0;

Answer 2

With regex you can do that, but it isn't optimal nor fast at all, @hjpotter way if from far faster:

var_dump(strlen(preg_replace('~[^a-z]|(.)(?=.*\1)~i', '', $str)) == 26);

It removes all non letter characters, all duplicate letters (case insensitive), and compares the string length with 26.

• [^a-z] matches any non letter character
• (.) captures a letter in group 1
• (?=.*\1) checks if the same letter is somewhere else (on the right)
• the i modifier makes the pattern case insensitive