Problem Scenario 53 : You have been given below code snippet.

Solution :

valb = a.filter(_%2==0)

a.filter(_ < 4).collect

filter

Evaluates a boolean function for each data item of the RDD and puts the items for which the function returned true into the resulting RDD.

When you provide a filter function, it must be able to handle all data items contained in the RDD. Scala provides so-called partial functions to deal with mixed data types (Tip: Partial functions to deal are very useful if you have some data which may be bad and you do not want to handle but for the good data (matching data) you want to apply some Kind of map function. The following article is good. It teaches you about partial functions in a very nice way and explains why case has to be used for partial functions:article)

Examples for mixed data without partial functions

val b = sc.parallelize(1 to 8)

b.filter(_ < 4)xollect

res15: Arrayjlnt] = Array(1, 2, 3)

val a = sc.parallelize(List("cat'\ "horse", 4.0, 3.5, 2, "dog"))

a.filter(_<4).collect

error: value < is not a member of Any