$childrens = do_shortcode( '[products ids="'. $string . '"]' );
// function that runs when shortcode is called
function wpb_demo_shortcode() {
// Things that you want to do.
$message = 'Hello world!';
// Output needs to be return
return $message;
}
// register shortcode
add_shortcode('greeting', 'wpb_demo_shortcode');