Groovy script help with exporting the result (only failed ones)

Hi,

I was wondering if someone could help me with the groovy script to export the result into excel sheet. I am using 'data source loop' to loop through the set of data (Username). What I am trying to do is, export the result in excel sheet for the failed ones. for example, if the the third row of data fails, I want to export the user name of third row and with status code 'Failed'. 

Thank you!

Hari