Random selection of items in a slot

Rhythmyx Technical Discussion
1

Hello,

Does anyone know if it is possible to set up a slot so that it picks content items at random? For example, if you have hundreds of “product” content items in your Rhythmyx (6.5.2) system, and have set up a daily publishing schedule, how could you implement a “Product of the Day” box on the web site’s front page?

Thanks,

Andrew.

2

Andrew,

I don’t have the whole answer to this, but I’m pretty sure you could do this with $user.psoSlotTools.getSlotContents() and $tools.math.random().

If you specify a “floor” of 0 and a “ceiling” equal to the size of the slot contents, then the random() function should give you a whole number that matches some item in the slot.

You’ll probably have to play with it some to get the exact syntax right.

Dave

3

Thanks Dave, that sounds reasonable. At this point we just wanted to know that it is possible in Rhythmyx. I’ll try to remember to post back here when I try to implement it.

Andrew.

4

Here is the code I have developed. It can be used between an #initslot() and a #endslot():


#set($num_matching_items = $sys.currentslot.relresults.size())##

#if($num_matching_items > 0)##
	<ul>
	## Create a copy of the results arraylist, so we can remove matches as we go, to prevent 
	## randomly picking the same item twice. The foreach loop fails if this is done to the original $sys.currentslot.relresults arraylist
	#set($cloned_results = $sys.currentslot.relresults.clone())##

	## Loop thru all matching items. In each iteration we are going to randomly pick another item to display
	## and ignore $relresult. If there was a while loop in Velocity, this would be more efficient
	#foreach($relresult in $sys.currentslot.relresults)##
		#if($max_results > 0)##
			<li>
				## Pick an item at random
				#set($random_index = $tools.math.random(0,$num_matching_items))##

				## Display the randomly chosen item
				#slotItem($cloned_results.get($random_index))##

				## Remove item from the cloned arraylist, so it cannot be picked again (enclose 
				## in if statement to prevent outputting the removed item
				#if($cloned_results.remove($random_index)) #end##

				## Decrement counter to keep track of the number of items displayed
				#set($max_results = $tools.math.sub($max_results,1))##

				## Decrement upper limit so the random number next time will be one of the remaining items not yet displayed
				#set($num_matching_items = $tools.math.sub($num_matching_items,1))##
			</li>
		#end##
	#end##
	</ul>
#end##

$max_results needs to be set to an integer less than the number of items (otherwise you get everything, and only the order is random.)

5

Great work. Now I can junk the Javascript I was trying to create, in the thread on numbering items in a list slot. To insert a random image on a home page, I added images to a list slot and inserted your code, minus some blank lines, into the template. To clarify the process, I’ve added the initslot here and set the max_results:

#initslot("sList" "")##
	## $max_results must be an integer. If it isn't less than the number of items, you get all items, but in random order.)
#set($max_results = 1)##
#set($num_matching_items = $sys.currentslot.relresults.size())##
etc.
...

and ended with #endslot(“sList”)##