Spark operator: RDD basic conversion operation (4) -union, intersection, subtract

Union

Def union (other: RDD [T]): RDD [T]
The function is relatively simple, that is, the two RDD to merge, not to heavy .

    

  1.   Scala> var rdd1 = sc.makeRDD (1 to 2,1)
    2. 

  2.  Rdd1: org.apache.spark.rdd.RDD [Int] = ParallelCollectionRDD [45] at makeRDD at: 21
    3. 

  3.  
    4. 

  4.  Scala> rdd1.collect
    5. 

  5.  Res42: Array [Int] = Array (1, 2)
    6. 

  6.  
    7. 

  7.  Scala> var rdd2 = sc.makeRDD (2 to 3,1)
    8. 

  8.  Rdd2: org.apache.spark.rdd.RDD [Int] = ParallelCollectionRDD [46] at makeRDD at: 21
    9. 

  9.  
    10. 

  10.  Scala> rdd2.collect
    11. 

  11.  Res43: Array [Int] = Array (2, 3)
    12. 

  12.  
    13. 

  13.  Scala> rdd1.union (rdd2) .collect
    14. 

  14.  Res44: Array [Int] = Array (1, 2, 2, 3)
    15. 

  15.  
    16.

Intersection

Def intersection (other: RDD [T]): RDD [T]
Def node (other: RDD [T], numPartitions: Int): RDD [T]
Def intersection (other: RDD [T], partitioner: Partitioner) (implicit ord: Ordering [T] = null): RDD [T]
The function returns the intersection of two RDDs and goes to the weight .
Parameters numPartitions Specifies the number of partitions for the RDD returned.
The parameter partitioner is used to specify the partition function 
    

  1.   Scala> var rdd1 = sc.makeRDD (1 to 2,1)
    2. 

  2.  Rdd1: org.apache.spark.rdd.RDD [Int] = ParallelCollectionRDD [45] at makeRDD at: 21
    3. 

  3.  
    4. 

  4.  Scala> rdd1.collect
    5. 

  5.  Res42: Array [Int] = Array (1, 2)
    6. 

  6.  
    7. 

  7.  Scala> var rdd2 = sc.makeRDD (2 to 3,1)
    8. 

  8.  Rdd2: org.apache.spark.rdd.RDD [Int] = ParallelCollectionRDD [46] at makeRDD at: 21
    9. 

  9.  
    10. 

  10.  Scala> rdd2.collect
    11. 

  11.  Res43: Array [Int] = Array (2, 3)
    12. 

  12.  
    13. 

  13.  Scala> rdd1.intersection (rdd2) .collect
    14. 

  14.  Res45: Array [Int] = Array (2)
    15. 

  15.  
    16. 

  16.  Scala> var rdd3 = rdd1.intersection (rdd2)
    17. 

  17.  Rdd3: org.apache.spark.rdd.RDD [Int] = MapPartitionsRDD [59] at intersection at: 25
    18. 

  18.  
    19. 

  19.  Scala> rdd3.partitions.size
    20. 

  20.  Res46: Int = 1
    21. 

  21.  
    22. 

  22.  Scala> var rdd3 = rdd1.intersection (rdd2,2)
    23. 

  23.  Rdd3: org.apache.spark.rdd.RDD [Int] = MapPartitionsRDD [65] at intersection at: 25
    24. 

  24.  
    25. 

  25.  Scala> rdd3.partitions.size
    26. 

  26.  Res47: Int = 2
    27. 

  27.  
    28. 

  28.  
    29.

Subtract

Def subtract (other: RDD [T]): RDD [T]
Def subtract (other: RDD [T], numPartitions: Int): RDD [T]
Def subtract (other: RDD [T], partitioner: Partitioner) (implicit ord: Ordering [T] = null): RDD [T]
The function is similar to intersection, but returns an element that appears in RDD and does not appear in otherRDD.
Parameter meaning same intersection 
    

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

  2.  Rdd1: org.apache.spark.rdd.RDD [Int] = ParallelCollectionRDD [66] at makeRDD at: 21
    3. 

  3.  
    4. 

  4.  Scala> rdd1.collect
    5. 

  5.  Res48: Array [Int] = Array (1, 2, 2, 3)
    6. 

  6.  
    7. 

  7.  Scala> var rdd2 = sc.makeRDD (3 to 4)
    8. 

  8.  Rdd2: org.apache.spark.rdd.RDD [Int] = ParallelCollectionRDD [67] at makeRDD at: 21
    9. 

  9.  
    10. 

  10.  Scala> rdd2.collect
    11. 

  11.  Res49: Array [Int] = Array (3, 4)
    12. 

  12.  
    13. 

  13.  Scala> rdd1.subtract (rdd2) .collect
    14. 

  14.  Res50: Array [Int] = Array (1, 2, 2)
    15.

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