Concatenate Values

kevin_mkevin_m Member Posts: 5 Contributor I
edited December 2018 in Help

I am missing the concatenate function in Radoop like in Rapidminer Studio. In Studio I can concat grouped Values with the Aggregate Operator. In Radoop is this function not available. How can I illustrate this in Radoop?

Thanks in advance!

Best Answer

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    phellingerphellinger Employee, Member Posts: 103 RM Engineering
    Solution Accepted

    Hi Kevin,


    true, the Radoop Aggregate does not have a built-in concatenate option currently.


    You can use the Hive Script operator in this case with a modified version of the following script that demonstrates group concatenation on the Golf sample dataset (from the Sample repository), explanation is below.


    CREATE VIEW ##outputtable## AS 
    SELECT play, concat_ws(', ', sort_array(collect_set(outlook))) outlook_values
    FROM ##inputtable1##
    GROUP BY play

    The result will look like this:

    Screen Shot 2017-08-03 at 11.49.10.png


    The aggregation function here is collect_set that collects the distinct values from the outlook column. If you need all values instead of just the distinct values, use collect_list instead. The sort_array function is only required, if you want the value list to be deterministic and sorted. If not, it can be omitted. The concat_ws function concatenates the values from an array with the specified separator.


    I hope this helps,



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