40 - Spark RDD Transformations - map() using reduce() - Code Demo 3

@backstreetbrogrammer

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Chapter 07 - Spark RDD Transformations - map() using reduce() - Code Demo 3
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Transformation: map(func)
Return a new distributed dataset formed by passing each element of the source through a function func.

As RDDs are immutable, after applying the map transformation, new RDD is created.

The func is applied to each element, mapping it into a new element (the word mapping is used because it has a meaning similar to transforming but with the nuance of “creating a new version of” rather than “modifying”).

Example:

final var myList = myRdd.map(String::length).collect();
final var count = myRdd.map(String::length).count();
final var count = myRdd.map(String::length).map(v -: 1L).reduce(Long::sum);


Github: https://github.com/backstreetbrogrammer/11_JavaSpark

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