Spark核心操作--Transformation和Action

Transformations

把一个RDD（数据集合）转换成另一个RDD（数据集合）

•map

•filter

•flatMap

•mapPartitions

•mapPartitionsWithIndex

•sample

•union

•intersection

•distinct

•groupByKey

•reduceByKey

•aggregateByKey

•sortByKey

•join

•cogroup

•cartesian

•pipe

•coalesce

•repartition

•repartitionAndSortWithinPartitions

Action

返回给driver program一个计算结果

•reduce

•collect

•count

•first

•take

•takeSample

•takeOrdered

•saveAsTextFile

•saveAsSequenceFile

•saveAsObjectFile

•countByKey

•foreach