How do I get posts by multiple post ID’s?

Question 1

I’ve got a string with post ID’s: 43,23,65.
I was hoping I could use get_posts() and use the string with ID’s as an argument.

But I can’t find any functions for retrieving multiple posts by ID.

Do I really have to do a WP_query?

I’ve also seen someone mention using tag_in – but I can’t find any documentation on this.

Question 2

You can use get_posts() as it takes the same arguments as WP_Query.

To pass it the IDs, use 'post__in' => array(43,23,65) (only takes arrays).

Something like:

$args = array(
    'post__in' => array(43,23,65)
);

$posts = get_posts($args);

foreach ($posts as $p) :
    //post!
endforeach;

I’d also set the post_type and posts_per_page just for good measure.

3