Github user mateiz commented on a diff in the pull request:
https://github.com/apache/spark/pull/97#discussion_r11224851
--- Diff: python/pyspark/rdd.py ---
@@ -713,6 +780,31 @@ def merge(a, b):
return sorted(self.mapPartitions(topIterator).reduce(merge),
reverse=True)
+ def takeOrdered(self, num, key=None):
+ """
+ Get the N elements from a RDD ordered in ascending order or as
specified
+ by the optional key function.
+
+ >>> sc.parallelize([10, 1, 2, 9, 3, 4, 5, 6, 7]).takeOrdered(6)
+ [1, 2, 3, 4, 5, 6]
+ >>> sc.parallelize([10, 1, 2, 9, 3, 4, 5, 6, 7], 2).takeOrdered(6,
key=lambda x: -x)
+ [(-10, 10), (-9, 9), (-7, 7), (-6, 6), (-5, 5), (-4, 4)]
--- End diff --
Actually there is a problem here -- when you specify a key function, it
should only be used for sorting, it should not be returned in the final output.
So this code for example should return
```
[10, 9, 7, 6, 5, 4]
```
You probably need to make a pass after the merge if a key is given to
create a new array.
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