CHIA-MING LIN thinks this is interesting: (v) => (v, 1) From 4. Working with Key/Value Pairs from Learning Spark by Matei Zaharia, Patrick Wendell, Andy Konwinski, Holden Karau Publisher: O'Reilly Media, Inc. Released: February 2015 Note createCombiner: the return of this creator determines the type of accumulator. Share this highlight http://www.safaribooksonline.com/a/learning-spark/1246665/ Twitter Facebook Google Plus Email Get Instant Access Now Start a Free Trial Have an account? Sign in. Minimise Unlock the rest of Learning Spark and 30,000 other books and videos By clicking this box, you confirm that you have read and agree to the terms and conditions of our Membership Agreement, and you understand that when your trial period ends, you will be required to provide billing information if you wish to continue using the service. Unlock the rest of this book Start a Free 10-Day Trial loading Learn about Safari for Business Have an account? Sign in.