Github user andrewor14 commented on a diff in the pull request:
https://github.com/apache/spark/pull/93#discussion_r10362394
--- Diff: python/pyspark/rdd.py ---
@@ -628,6 +669,26 @@ def mergeMaps(m1, m2):
m1[k] += v
return m1
return self.mapPartitions(countPartition).reduce(mergeMaps)
+
+ def top(self, num):
+ """
+ Get the top N elements from a RDD.
+
+ Note: It returns the list sorted in ascending order.
+ """
+ def f(iterator):
+ q = BoundedPriorityQueue(num)
+ for k in iterator:
+ q.put(k)
+ return q
+
+ def f2(a, b):
+ a.put(b)
+ return a
+ q = BoundedPriorityQueue(num)
+ # I can not come up with a way to avoid this step.
+ t = self.mapPartitions(f).collect()
+ return [k for k in iter(reduce(f2, t, q))]
--- End diff --
This could just be ```list(reduce(f2, t, q))```
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