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

Abstracting data


Blaze can abstract many different data structures and expose a single, easy-to-use API. This helps to get a consistent behavior and reduce the need to learn multiple interfaces to handle data. If you know pandas, there is not really that much to learn, as the differences in the syntax are subtle. We will go through some examples to illustrate this.

Working with NumPy arrays

Getting data from a NumPy array into the DataShape object of Blaze is extremely easy. First, let's create a simple NumPy array: we first load NumPy and then create a matrix with two rows and three columns:

import numpy as np
simpleArray = np.array([
        [1,2,3],
        [4,5,6]
    ])

Now that we have an array, we can abstract it with Blaze's DataShape structure:

simpleData_np = bl.Data(simpleArray)

That's it! Simple enough.

In order to peek inside the structure you can use the .peek() method:

simpleData_np.peek()

You should see an output similar to what is shown in the following screenshot:

You can also use...