Apache Pig：将嵌套袋合并到一个袋中

Question

How can I merge a nested bag in Pig?

like

{{item1, item2}, {item3, item4}, {item5, item6}} 

to

{item1, item2, item3, item4, item5, item6} 

Answer 1

Just calling on flatten on multiple bags would create a cross-product. For your case, you probably need to convert the bags to tuple and then unnest the tuple by calling flatten. http://pig.apache.org/docs/r0.17.0/func.html#bagtotuple