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Learning PySpark

Learning PySpark

By : Drabas, Lee
3.9 (194)
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Learning PySpark

Learning PySpark

3.9 (194)
By: Drabas, 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 (13 chapters)
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12
Index

Getting to know your data


In order to build a statistical model in an informed way, an intimate knowledge of the dataset is necessary. Without knowing the data it is possible to build a successful model, but it is then a much more arduous task, or it would require more technical resources to test all the possible combinations of features. Therefore, after spending the required 80% of the time cleaning the data, we spend the next 15% getting to know it!

Descriptive statistics

I normally start with descriptive statistics. Even though the DataFrames expose the .describe() method, since we are working with MLlib, we will use the .colStats(...) method.

Note

A word of warning: the .colStats(...) calculates the descriptive statistics based on a sample. For real world datasets this should not really matter but if your dataset has less than 100 observations you might get some strange results.

The method takes an RDD of data to calculate the descriptive statistics of and return a MultivariateStatisticalSummary...

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