Ruby code to generate fields dynamically based on csv

[SreelekhaKovuri]

I need dynamically generated fields based on the CSV in the logs.
In this case my csv format can be in any of the following ways:
CSV =
CSV = 0
CSV = 1111;2222;3333;4444444;5555
CSV = 1;2;3;4;5;6;7;8;9;10

So, I want the fields to be created in the following way:
CSV01 = 1
CSV02 = 2
CSV03 = 3
.
.
.

For this I tired the following Ruby code in filter plugin

 ruby {
                        code => '
                                if event.get("CSV") != ""
                                        CSV_Numbers = event.get("CSV").split(";")
                                        for csvNumber in CSV_Numbers
                                                IndexValue = event.get("CSV").index("csvNumber")
                                                fieldName = event.set("CSV0" + IndexValue)
                                                event.set("fieldName", csvNumber)
                                        end
                                end
                              '
                }

But I'm not able to generate fields dynamically. Can someone please help me in this case.

[Badger]

There are several issues with your code. In Ruby names that start with an upper case letter are constants, not variables, so once the first event has set CSV_Numbers it cannot be changed. Similarly for IndexValue. Also, you want fieldName to be a ruby variable, not a field on the event, so do not use event.set.

I would do this using

    ruby {
        code => '
            csv = event.get("CSV")
            if csv != ""
                csvNumbers = csv.split(";")
                csvNumbers.each_index { |x|
                    event.set("CSV0#{x}", csvNumbers[x])
                }
            end

        '
    }

[SreelekhaKovuri]

Thanks @Badger !!
That actually helped.