#transformations
常用的Transformation与Action API举例。...9,全局聚合后的结果还需与初始值相加,结果为14+5=19
aggregate全局聚合是无序的
scala> val rdd2 = sc.parallelize(List("a","b","c","d"...0,与"12".length=2 相比,0更小,执行0.toString,返回"0"。...#countByKey 求某个Key出现的次数,与数值没有关系
scala> val rdd1 = sc.parallelize(List(("a", 1), ("b", 2), ("b", 2), (...(b,2) -> 2, (c,2) -> 1, (a,1) -> 1, (c,1) -> 1)
#filterByRange [是一个闭区间,包含了例子所示的"b"与"d"]
scala> val