If single/category

the array($settings['excl_post']) is just putting the contents of $settings['excl_post'] into a single element in an array. If the contents of $settings['excl_post'] are comma separated post ids, try this:

$exclude_array = explode(',' $settings['excl_post']);
if(is_single($exclude_array)){ ...

You may also need to run a loop over each item in $exclude_array and get the intval() of the item to make sure what you’re holding in the array is an integer, bu tI’m not sure.

Unfortunely it doesn’t work, but with a loop is great. ?? Thank you! ??

$exclude_array = explode(",", $settings['excl_post']);
	for ( $i = 0; $i < count($exclude_array); $i++ ) {
	if(is_single($exclude_array[$i])==true) {...} }

But I have one more question. Is it possible to use any conditional tag to check if element is in specific class or id (like div id="sidebar")?

Glad to hear you got it working.

If I understand your second question properly, no, I dont believe there’s a way to check that. If you explain what you’re trying to do though, maybe we could come up with a different method.