Associating related entries to a new entry when using the API
I dont think you can build arrays in PHP that way and you end up passing array(0 =&gt; '1021,1047,1076,1123') to the param.

Not shure if passing the string is supported:

'article_countries' =&gt; $article_countries


If not you could build the array like so:

'article_countries' =&gt; array_map('trim', explode(',', $article_countries))