Open Refine - Regroup rows values by column values

Question

I am new Open refine user and don't know how to code.

I would like to group multiple values of a column compared to an other column.

I have this file

ID 1	ID 2
ID1.1	ID2.1
ID1.1	ID2.2
ID1.2	ID2.3
ID1.2	ID2.4
ID1.2	ID2.5

And i'd like to have this one :

ID 1	ID 2
ID1.1	ID2.1;ID2.2
ID1.2	ID2.3;ID2.4;ID2.5

The file got 150k lines and multiple columns

I tried to Add a new column based on the first column, but I don't how to group the values of the row1, row2, row3... of the second column based on the value of the first column.

Thank you for any answer

Answer 1

• Switch to record mode by using blank down on the column ID 1
• Use the following GREL in ID 2 with forEach(row.record.cells['ID 2'].value,v,v).join(';') to join data in the first cell
• Delete the unwanted record by going back to rows mode, and bulk editing row where ID 1 is blank

Video recording of the steps: https://youtu.be/p6urT-CO76s