Book Image

Hands-On Big Data Analytics with PySpark

By : Rudy Lai, Bartłomiej Potaczek
Book Image

Hands-On Big Data Analytics with PySpark

By: Rudy Lai, Bartłomiej Potaczek

Overview of this book

Apache Spark is an open source parallel-processing framework that has been around for quite some time now. One of the many uses of Apache Spark is for data analytics applications across clustered computers. In this book, you will not only learn how to use Spark and the Python API to create high-performance analytics with big data, but also discover techniques for testing, immunizing, and parallelizing Spark jobs. You will learn how to source data from all popular data hosting platforms, including HDFS, Hive, JSON, and S3, and deal with large datasets with PySpark to gain practical big data experience. This book will help you work on prototypes on local machines and subsequently go on to handle messy data in production and at scale. This book covers installing and setting up PySpark, RDD operations, big data cleaning and wrangling, and aggregating and summarizing data into useful reports. You will also learn how to implement some practical and proven techniques to improve certain aspects of programming and administration in Apache Spark. By the end of the book, you will be able to build big data analytical solutions using the various PySpark offerings and also optimize them effectively.
Table of Contents (15 chapters)

Sampling/filtering RDDs to pick out relevant data points

In this section, we will look at sampling and filtering RDDs to pick up relevant data points. This is a very powerful concept that allows us to circumvent the limitations of big data and perform our calculations on a particular sample.

Let's now check how sampling not only speeds up our calculations, but also gives us a good approximation of the statistic that we are trying to calculate. To do this, we first import the time library as follows:

from time import time

The next thing we want to do is look at lines or data points in the KDD database that contains the word normal:

raw_data = sc.textFile("./kdd.data.gz")

We need to create a sample of raw_data. We will store the sample into the sample, variable, and we're sampling from raw_data without replacement. We're sampling 10% of the data, and we...