How to add count value to each csv value in logstash

I have some csv, and with ruby i convert it to array , like this:

11;22;33;44;55
66;77;88;99;100


 ruby {
     code => '
         m = event.get("message").split(";")
         m.each_index { |x| m[x] = m[x].to_f }
         event.set("[messages]", m)
     '
 }

Output is:

"hits" : [
  {
    "_index" : "array_werte_v1",
    "_type" : "_doc",
    "_id" : "6pKOgngBVrDB9qxVPT4F",
    "_score" : 1.0,
    "_source" : {
      "path" : "/home/ofitz-elk/bueltmann/stab001/array_werte.csv",
      "column1" : "66;77;88;99;100",
      "host" : "ofitz_elk-ingest-node_0321",
      "@version" : "1",
      "@timestamp" : "2021-03-30T09:54:22.590Z",
      "message" : [
        66.0,
        77.0,
        88.0,
        99.0,
        100.0
      ]

i need additional array wit the count values of the array message like new field "message_count":

    "hits" : [
    {
    "_index" : "array_werte_v1",
    "_type" : "_doc",
    "_id" : "6pKOgngBVrDB9qxVPT4F",
    "_score" : 1.0,
    "_source" : {
      "path" : array_werte.csv",
      "column1" : "66;77;88;99;100",
      "host" : "host_0321",
      "@version" : "1",
      "@timestamp" : "2021-03-30T09:54:22.590Z",
      "message" : [ 66.0, 77.0,  88.0, 99.0, 100.0 ],
      "message_count" : [ 1,  2,  3,  4,  5 ]
 ]