Book Image

Learning PySpark

By : Tomasz Drabas, Denny Lee
Book Image

Learning PySpark

By: Tomasz Drabas, Denny Lee

Overview of this book

Apache Spark is an open source framework for efficient cluster computing with a strong interface for data parallelism and fault tolerance. This book will show you how to leverage the power of Python and put it to use in the Spark ecosystem. You will start by getting a firm understanding of the Spark 2.0 architecture and how to set up a Python environment for Spark. You will get familiar with the modules available in PySpark. You will learn how to abstract data with RDDs and DataFrames and understand the streaming capabilities of PySpark. Also, you will get a thorough overview of machine learning capabilities of PySpark using ML and MLlib, graph processing using GraphFrames, and polyglot persistence using Blaze. Finally, you will learn how to deploy your applications to the cloud using the spark-submit command. By the end of this book, you will have established a firm understanding of the Spark Python API and how it can be used to build data-intensive applications.
Table of Contents (20 chapters)
Learning PySpark
Credits
Foreword
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Creating DataFrames


Typically, you will create DataFrames by importing data using SparkSession (or calling spark in the PySpark shell).

Tip

In Spark 1.x versions, you typically had to use sqlContext.

In future chapters, we will discuss how to import data into your local file system, Hadoop Distributed File System (HDFS), or other cloud storage systems (for example, S3 or WASB). For this chapter, we will focus on generating your own DataFrame data directly within Spark or utilizing the data sources already available within Databricks Community Edition.

Note

For instructions on how to sign up for the Community Edition of Databricks, see the bonus chapter, Free Spark Cloud Offering.

First, instead of accessing the file system, we will create a DataFrame by generating the data. In this case, we'll first create the stringJSONRDD RDD and then convert it into a DataFrame. This code snippet creates an RDD comprised of swimmers (their ID, name, age, and eye color) in JSON format.

Generating our own JSON...