title: How to combine two rdd into on rdd in spark(Python)
body: <p>For example, there are two rdds such as "rdd1 = [[1,2],[3,4]], rdd2 = [[5,6],[7,8]]". And how to combine both into this style: [[1,2,5,6],[3,4,7,8]]. Is there any function can solve this problem? </p>