Unable to concat or process data

[Anonymous]

The data provided to me is as follows 

a

b

c

The result i want is 

a

a,b

a,b,c

I tried using tloop along with tjava to complete it but couldn't do it also tried taggregator but it works only for numbers  

[akumar2301 · Accepted solution]

today someone else asked the same question 

https://community.talend.com/t5/Design-and-Development/How-achive-cummlative-sum-in-talend/m-p/15797...