How to programmatically add / remove a value for an unlimited multivalue field?
You can use the entity_metadata_wrapper() function with entities (you'll find good examples here); it makes things a bit cleaner, but not that much.

Other than that, no - you're stuck using vanilla PHP for this, Drupal doesn't have any built in functions to help.

There's no reason you can't use array_push as normal though:

array_push($myfield[LANGUAGE_NONE], array('value' =&gt; 23424));


Although that's actually more verbose and less readable than the original.