Spark Operator: RDD Action Action (2) -take, top, takeOrdered

Take

Def take (num: Int): Array [T]
Take is used to get RDD from 0 to num-1 subscript elements, not sort. 
    

  1.   Scala> var rdd1 = sc.makeRDD (Seq (10, 4, 2, 12, 3))
    2. 

  2.  Rdd1: org.apache.spark.rdd.RDD [Int] = ParallelCollectionRDD [40] at makeRDD at: 21
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  4.  Scala> rdd1.take (1)
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  5.  Res0: Array [Int] = Array (10)                                                    
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  7.  Scala> rdd1.take (2)
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  8.  Res1: Array [Int] = Array (10, 4)
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    10.

Top

Def top (num: Int) (implicit ord: Ordering [T]): Array [T]
The top function is used to return the preceding num elements from RDD, by default (descending) or by the specified collation. 
    

  1.   Scala> var rdd1 = sc.makeRDD (Seq (10, 4, 2, 12, 3))
    2. 

  2.  Rdd1: org.apache.spark.rdd.RDD [Int] = ParallelCollectionRDD [40] at makeRDD at: 21
    3. 

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  4.  Scala> rdd1.top (1)
    5. 

  5.  Res2: Array [Int] = Array (12)
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  7.  Scala> rdd1.top (2)
    8. 

  8.  Res3: Array [Int] = Array (12, 10)
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  10.  // specify collation scala> implicit val myOrd = implicitly [Ordering [Int]]. Reverse
    11. 

  11.  MyOrd: scala.math.Ordering [Int] = scala.math.Ordering$$anon$4@767499ef
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  13.  Scala> rdd1.top (1)
    14. 

  14.  Res4: Array [Int] = Array (2)
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  16.  Scala> rdd1.top (2)
    17. 

  17.  Res5: Array [Int] = Array (2, 3)
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TakeOrdered

Def takeOrdered (num: Int) (implicit ord: Ordering [T]): Array [T]
TakeOrdered is similar to top, except that the elements are returned in the reverse order of top. 
    

  1.   Scala> var rdd1 = sc.makeRDD (Seq (10, 4, 2, 12, 3))
    2. 

  2.  Rdd1: org.apache.spark.rdd.RDD [Int] = ParallelCollectionRDD [40] at makeRDD at: 21
    3. 

  3.  
    4. 

  4.  Scala> rdd1.top (1)
    5. 

  5.  Res4: Array [Int] = Array (2)
    6. 

  6.  
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  7.  Scala> rdd1.top (2)
    8. 

  8.  Res5: Array [Int] = Array (2, 3)
    9. 

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    10. 

  10.  Scala> rdd1.takeOrdered (1)
    11. 

  11.  Res6: Array [Int] = Array (12)
    12. 

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    13. 

  13.  Scala> rdd1.takeOrdered (2)
    14. 

  14.  Res7: Array [Int] = Array (12, 10)
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For more information on the Spark operator, refer to the Spark operator series .

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