如何在Spark / Scala中将Array [String]转换为Array [Any]

Question

I am trying to generate sourceIds for the parallelPersonalizedPageRank algorithm inside Graphframes and call the algoirthm as following:

val PPRIdCS = studentCS.select("id").collect.map(row => row.getString(0))
val ranksCS = studentGraph
  .parallelPersonalizedPageRank
  .resetProbability(0.15)
  .maxIter(10)
  .sourceIds(PPRIdCS)
  .run()

The error information I got is as following:

Message: <console>:46: error: type mismatch;
found   : Array[String]
required: Array[Any]
Note: String <: Any, but class Array is invariant in type T.
You may wish to investigate a wildcard type such as `_ <: Any`. (SLS 
3.2.10).sourceIds(PPRIdCS)

I could not figure out what is the way to cast a String type to Any type, or a way to map String to Any while generating PPRIdCS. Thanks!

Answer 1

As noted from my comment, you can map to .asInstanceOf[Any].

Example:

val arr = Array("a", "b") 
val asAny = arr.map(_.asInstanceOf[Any])

This also appears to work...

val asAny = arr.asInstanceOf[Array[Any]]

Now doing this is assuming you for some reason do not want to specify the type explicitly as noted by the other answer.

Answer 2

Just be explicit about the types:

val PPRIdCS: Array[Any] = studentCS.select("id").collect.map(row => row.getString(0))

or better

val PPRIdCS: Array[Any] = studentCS.select("id").collect.map(row => row(0))