Sign In Start Free Trial
Account

Add to playlist

Create a Playlist

Modal Close icon
You need to login to use this feature.
  • Book Overview & Buying Mastering Hadoop
  • Table Of Contents Toc
Mastering Hadoop

Mastering Hadoop

By : Karanth
4 (3)
close
close
Mastering Hadoop

Mastering Hadoop

4 (3)
By: Karanth

Overview of this book

Do you want to broaden your Hadoop skill set and take your knowledge to the next level? Do you wish to enhance your knowledge of Hadoop to solve challenging data processing problems? Are your Hadoop jobs, Pig scripts, or Hive queries not working as fast as you intend? Are you looking to understand the benefits of upgrading Hadoop? If the answer is yes to any of these, this book is for you. It assumes novice-level familiarity with Hadoop.
Table of Contents (15 chapters)
close
close
14
Index

The advanced Pig operators


In this section, we will examine some of the advanced features and hints available in Pig operators.

The advanced FOREACH operator

The FOREACH operator is primarily used to transform every record of the input relation into a transformed record. A list of expressions is used to make this transformation. There are situations where the FOREACH operator can increase the number of output records. They are discussed in the following sections.

The FLATTEN operator

The FLATTEN keyword is an operator, though it looks like a UDF in syntax. It is used to un-nest nested tuples and bags. However, the semantics of the elimination of nesting is different when it is used on tuples when compared to bags.

FLATTEN on a nested tuple yields a single tuple, as shown in the following snippet. All the nested tuples are elevated to the topmost level.

Consider data of the following nature:

(1, (2, 3, 4)) 
X = FOREACH A GENERATE $0, FLATTEN($1); 

This will yield (1,2,3,4) as the resulting tuple...

CONTINUE READING
83
Tech Concepts
36
Programming languages
73
Tech Tools
Icon Unlimited access to the largest independent learning library in tech of over 8,000 expert-authored tech books and videos.
Icon Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.
Icon 50+ new titles added per month and exclusive early access to books as they are being written.
Mastering Hadoop
notes
bookmark Notes and Bookmarks search Search in title playlist Add to playlist font-size Font size

Change the font size

margin-width Margin width

Change margin width

day-mode Day/Sepia/Night Modes

Change background colour

Close icon Search
Country selected

Close icon Your notes and bookmarks

Confirmation

Modal Close icon
claim successful

Buy this book with your credits?

Modal Close icon
Are you sure you want to buy this book with one of your credits?
Close
YES, BUY

Submit Your Feedback

Modal Close icon
Modal Close icon
Modal Close icon