3v4l.org

run code in 300+ PHP versions simultaneously
<?php $string = '{},\"employees\":{},\"idIwant\":{\"2545\":{\"attributes\":{\"offset\":9855,'; echo preg_match('~"idIwant\\\":{\\\"\K\d+~', $string, $out) ? $out[0] : 'bonk';
Output for 7.1.25 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
2545
preferences:
79.98 ms | 1488 KiB | 4 Q