Apache Spark RDD operations : Transformations and Actions скачать в хорошем качестве

Apache Spark RDD operations : Transformations and Actions

Official Website: http://bigdataelearning.com RDD operations ============== There are 2 operations that can be applied on RDD. One is transformation. 1) Transformation =============== Transformation is what you do to an RDD to get another resultant RDD. The example would be to apply functions like filter, union , that would then create another resultant RDD. FILTER is a transformation that when applied on an RDD, will isolate certain elements and create a new RDD. This combining of elements from 2 RDD be done using UNION transformation. UNION is a multi-RDD transformation, which means it acts on more than one RDD. 2) Actions ========= Actions are second type of operations in RDD. Actions return a result to the driver program , or write it in a storage and kick off a computation. some examples are count , first, collect, take count action can be used to get the number of elements in an RDD. ---------- first action can be used to retrieve the first element in the RDD. ------- take action can be used to retrieve n elements out of the RDD. -------- collect action can be used to retrieve the complete list of elements ----------- from the RDD.