https://issues.apache.org/jira/browse/SPARK-1540
https://github.com/apache/spark/commit/640f9a0efefd42cff86aecd4878a3a57f5ae85fa


On Wed, Jun 4, 2014 at 8:14 PM, Wenchen Fan <notifications@github.com>
wrote:

> In core/src/main/scala/org/apache/spark/rdd/RDD.scala:
>
> > @@ -423,6 +423,18 @@ abstract class RDD[T: ClassTag](
> >    def ++(other: RDD[T]): RDD[T] = this.union(other)
> >
> >    /**
> > +   * Return this RDD sorted by the given key function.
> > +   */
> > +  def sortBy[K](
> > +      f: (T) ⇒ K,
> > +      ascending: Boolean = true,
> > +      numPartitions: Int = this.partitions.size)
> > +      (implicit ord: Ordering[K], ctag: ClassTag[K]): RDD[T] =
>
> @markhamstra <https://github.com/markhamstra> I checked RDD.scala and
> found the style you talked about. But one thing I don't understand is:def
> countByValue()(implicit ord: Ordering[T] = null). I can't find the use of
> implicit Ordering[T] anywhere inside the method, and I compiled spark
> successfully with this implicit Ordering[T] removed. Did I miss something
> here?
>
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> <https://github.com/apache/spark/pull/369/files#r13422474>.
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