Preg Replace - replace second occurance of a match

Question

I am relatively new to php, and hope someone can help me with a replace regex, or maybe a match replace I am not exactly sure.

I want to automatically bold the (seco

Answer 1

The regular expression itself cannot count, and the preg_ functions provide little help. You need a workaround. If you were to actually search for just a word, you might want to use string functions. Otherwise try:

// just counting
if (7 >= preg_match_all($pattern, $subject, $matches)) {

   $cb_num = 0;
   $subject = preg_replace_callback($pattern, "cb_ibu", $subject);
}

function cb_ibu($match) {
    global $cb_num;

    $match = $match[0];

    switch (++$cb_num) {
        case 2: return "$match";
        case 4: return "$match";
        case 7: return "$match";
        default: return $match;
    }
}

The trick is to have a callback which does the accounting. And there it's quite easy to add any rules.