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 the final dataset


Therefore, it is time to create our final dataset that we will use to build our models. We will convert our DataFrame into an RDD of LabeledPoints.

A LabeledPoint is a MLlib structure that is used to train the machine learning models. It consists of two attributes: label and features.

The label is our target variable and features can be a NumPy array, list, pyspark.mllib.linalg.SparseVector, pyspark.mllib.linalg.DenseVector, or scipy.sparse column matrix.

Creating an RDD of LabeledPoints

Before we build our final dataset, we first need to deal with one final obstacle: our 'BIRTH_PLACE' feature is still a string. While any of the other categorical variables can be used as is (as they are now dummy variables), we will use a hashing trick to encode the 'BIRTH_PLACE' feature:

import pyspark.mllib.feature as ft
import pyspark.mllib.regression as reg
hashing = ft.HashingTF(7)
births_hashed = births_transformed \
    .rdd \
    .map(lambda row: [
            list(hashing.transform...