Fold multiple columns

This processor takes values from multiple columns and transforms them to one line per column.

For example, with the following dataset representing monthly scores:

person

age

01/2014

02/2014

03/2014

John

24

3

4

3

Sidney

31

6

9

Bill

33

1

4

We would like to get one line per (month, person) couple with the score.

Applying the processor with:

  • 3 columns in the “columns list”: 01/2014, 02/2014, 03/2014

  • “month” as the “fold name column”

  • “score” as the “fold value column”

will generate the following result:

person

age

month

score

John

24

01/2014

3

John

24

02/2014

4

John

24

03/2014

6

Sidney

31

01/2014

Sidney

31

02/2014

6

Sidney

31

03/2014

9

Bill

33

01/2014

1

Bill

33

02/2014

Bill

33

03/2014

4

  • The names of the folded columns are used as values of the “fold name column”

  • The values of the folded columns are used as values of the “fold values column”

  • The folded columns are removed

  • All other columns are copied

  • Empty values are preserved in the folded result

For more details on reshaping, please see Reshaping.