Finally, there's the unpack_arrays setting. Let us change the data for our node again to look as follows, while leaving the common data the same:

# mynode.myorg.net.yaml
 classification:
   classes:
     - --paessler,nagios
     - webserver
 

The unpack_arrays setting takes each string, splits it according to the , delimiter, creating an array of, in our example, [“–-paessler”, “nagios”], and then merging it; in our example knocking out the paessler value, since it was indicated with the knockout_prefix as follows:

lookup({
   'name'  => 'classification',
   'merge' => {
     'strategy'        => 'deep',
     'knockout_prefix' => '--',
     unpack_arrays     =>’,’,
   },
 })