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

Determining the most popular non-stop flights


Expanding upon our tripGraph GraphFrame, the following query will allow us to find the most popular non-stop flights in the US (for this dataset):

# Determine the most popular non-stop flights
import pyspark.sql.functions as func
topTrips = tripGraph \
  .edges \
  .groupBy("src", "dst") \
  .agg(func.count("delay").alias("trips"))

# Show the top 20 most popular flights (single city hops)
display(topTrips.orderBy(topTrips.trips.desc()).limit(20))

Note, while we are using the delay column, we're just actually doing a count of the number of trips. Here's the output:

As can be observed from this query, the two most frequent non-stop flights are between LAX (Los Angeles) and SFO (San Francisco). The fact that these flights are so frequent indicates their importance in the airline market. As noted in the New York Times article from April 4, 2016, Alaska Air Sees Virgin America as Key to West Coast (http://nyti.ms/2ea1uZR), acquiring slots at these two...