Filtering aerospike LLIST - php

Question

Can anyone please show me how to filter an Aerospike LLIST bin not by the key and return all the result using PHP.
In my case the bin 'notes' is containing many rows of key, title, desc & category. I can retrieve all rows using the following code but
I need to do a filter on the category and get the results of only those within the same category. If udf is needed please assist to show me the udf code as well and how to apply the filter to get the results.
$db = new Aerospike($config, false);<br/>
$key = $db->initKey('mynamespace', 'myset', $userid);<br/>
$list = new \Aerospike\LDT\LList($db, $key, 'notes');<br/>
$status = $list->scan($results);

Answer 1

The LList.scan method has an optional module name, function name pair of parameters, allowing you to call a Lua function to filter each element.
There's an example PHP script provided with the client repo, which calls an example Lua module:
function keyfilters.even_filter(element)
local remainder = -1
if type(element) == "number" then
remainder = element % 2
elseif (getmetatable(element) == getmetatable(map())) and element['key'] then
remainder = element['key'] % 2
end
if remainder == 0 then
return element
else
return nil
end
end
Is invoked by
$rental_history->scan($elements, 'keyfilters', 'even_filter');

Answer 2

Manage to modify the UDF as follows and it works.
local category_filters = {}
function category_filters.filterBy(element,val)
if element['category'] == val[1] then
return element
else
return nil
end
end
return category_filters
Invoked by
$status = $list->scan($results, 'category_filters', 'filterBy', array($category));