Use of Split Filter for more than 1 fields, it is possible

[magnusbaeck (Magnus Bäck)]

The split filter acts on a single field. You can use a ruby filter to join the elements of each array into another array so that you have this:

{
  ...
  "field_to_split": [
    ["A", "E", "W", "Q"],
    ...
  ]
}

Then feed field_to_split to a split filter, and use another filter or two to split the array back into discrete fields.