<?php
// example code
$content = 'dasdasdas d asdas dasdas dasd [gallery ids="2727,2726,2721"] dasd as ads';
$ids = substr(strstr($content, '[gallery ids='), 14);
$ids = substr($ids, 0, strpos( $ids, '"]'));
$ids = explode(',', $ids);
$your_shortcodes = preg_match_all( '#[gallery*.*?]#s', $content, $matches );
print_r($matches);
echo print_r($ids);
preferences:
40.09 ms | 402 KiB | 5 Q