I have a simple function:
implicit class ArrayView[A](self: Array[A]) {
def filterByType[B <: A: ClassTag]: Array[B] = {
val ctg = implicitly[ClassTag[B]]
val runtimeClazz = ctg.runtimeClass
self.flatMap{
v =>
if (v.getClass.isAssignableFrom(runtimeClazz)) Some(v.asInstanceOf[B])
else None
}.toArray
}
}
and a simple test case:
assert(Array(1, 2.2, "a").filterByType[Int].toSeq == Seq(1))
assert(Array(1, 2.2, "a").filterByType[java.lang.Integer].toSeq == Seq(1: java.lang.Integer))
assert(Array(1, 2.2, "a").filterByType[Double].toSeq == Seq(2.2))
assert(Array(1, 2.2, "a").filterByType[java.lang.Double].toSeq == Seq(2.2: java.lang.Double))
assert(Array(1, 2.2, "a").filterByType[String].toSeq == Seq("a"))
it only works in Scala >2.11.3 (because of https://issues.scala-lang.org/browse/SI-6967 , this has been brought about for some time), but many libraries (eg spark-hive_thriftserver) still have problems being ported to 2.11, while 2.10 has been largely stable for most other cases, is there a quick patch for this bug?
OK this is really funky, but whatever:
implicit class ArrayView[A](self: Array[A]) {
def filterByType[B <: A: ClassTag]: Array[B] = {
self.flatMap{
v =>
try {
Array[B](v.asInstanceOf[B])
}
catch {
case e: Throwable =>
Array[B]()
}
}.toArray
}
}
pass all the tests
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