Can one of the Scala experts please explain this bit of pattern magic from
the Spark ML tutorial: _._2.user ?
As near as I can tell, this is applying the _2 function to the wildcard, and
then applying the Œuser¹ function to that. In a similar way the Œproduct¹
function is applied in the next
ratings is an RDD of Rating objects. You can see them created as the
second element of the tuple. It's a simple case class:
https://github.com/apache/spark/blob/master/mllib/src/main/scala/org/apache/spark/mllib/recommendation/ALS.scala#L66
This is just accessing the user and product field of
Hi Steve,
The _ notation can be a bit confusing when starting with Scala, we can
rewrite it to avoid using it here. So instead of
val numUsers = ratings.map(_._2.user) we can write val numUsers =
ratings.map(x = x._2.user)
ratings is an Key-Value RDD (which is an RDD comprised of tuples) and so
