Using PHP loops results

I must be cracking up, but I can't seem to save my loop increments and use them outside the loop.

What I'm trying to do is create a string variable and use it elsewhere in the page. I'm using a loop to generate it. But I don;t want to use the string inside the loop itself.

So when I try to echo the varilable outside the loop after the loop has finished all I'm getting is the final iteration of the loop:

for($i=$insertUpInit;$i<=50;$i++){
	
$actionInsertItems="action".$i;
$actionInsertItems=$actionInsertItems.',';
	
//here i get full list of items I need
echo $actionInsertItems;
}//end loop

//here i just get end item
echo $actionInsertItems;

I know that once someone points me in the right direction I'll slap my forhead quite hard.

Help a brother out!