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 “Split multiple columns” 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