计算preg_replace正则表达式中的出现次数

I know that with I can find of occurrences with preg_match_all
i.e.

<?php
$text = 'here is JUICE. it is good JUICE...';
$counted    = preg_match_all('/JUICE/',$text,$empt);
echo $counted;
?>

but how can I count occurrences with preg_replace?

As per the manual, there is an optional 5th parameter $count, which will be set to the number of replacements performed:

preg_replace($pattern, $replacement, $subject, -1, $count)

The 4th parameter is the $limit on the number of replacements. -1 means no limit.