Tracking issue: Implementation of lacking core RDD ops

[iduartgomez]

For core RDD ops we understand those which spawn in the original Apache Spark from SparkContext and/or the base RDD class and friends: SC:

• [x] range
• [x] filter
• [x] randomSplit
• [ ] sortBy
• [x] groupBy
• [x] keyBy
• [ ] zipPartitions
• [x] intersection
• [ ] pipe
• [x] zip
• [ ] substract
• [ ] treeAggregate
• [ ] treeReduce
• [x] countApprox
• [x] countByValue
• [x] countByValueApprox
• [x] min and max
• [x] top
• [x] takeOrdered
• [x] isEmpty

Non-goals for this tracking issue are any I/O related ops as we are tracking those elsewhere and doing things a little bit differently:

• textFile
• wholeTextFiles
• binary files | binary records
• Hadoop* family of methods

[iduartgomez]

Intersection completed in #66

[iduartgomez]

range done in #82

[GavrielPlotke]

@iduartgomez - Isn't substract a misspelling of subtract ?

[rajasekarv]

fixed @GavrielPlotke

[ajprabhu09]

what would the subtract operation entail, can someone give an example?

[GavrielPlotke]

Doc: https://spark.apache.org/docs/1.0.2/api/java/org/apache/spark/rdd/RDD.html#subtract(org.apache.spark.rdd.RDD) Example:

• I have a list of customers that I want to advertise to
• I have a list of angry customers who have said "DON'T TALK TO ME!" email_list_rdd = customers_rdd.subtract(angry_rdd)