Online PHP editor | output for 4OtdB

<?php $usPhone = '800-000-0010'; $regex = <<<'REGEX' ~ (?: ([1-9]\d)(?=(?:\d{2})?$) # 1: double-digit in last segment |(0) # 2: zero |([1-9]) # 3: single digit ) -? # consume optional delimiter ~x REGEX; $f = new NumberFormatter('en', NumberFormatter::SPELLOUT); echo ltrim( preg_replace_callback( $regex, fn($m) => sprintf( ' %s', array_key_last($m) === 2 ? 'oh' : $f->format(intval($m[0])) ), $usPhone ) );