Pyspark tutorial

PySpark
i
AbouttheTutorial
Apache Spark is written in Scala programming language. To support Python with Spark,
Apache Spark community released a tool, PySpark. Using PySpark, you can work with
RDDs in Python programming language also. It is because of a library called Py4j that they
are able to achieve this.
This is an introductory tutorial, which covers the basics of Data-Driven Documents and
explains how to deal with its various components and sub-components.
Audience
This tutorial is prepared for those professionals who are aspiring to make a career in
programming language and real-time processing framework. This tutorial is intended to
make the readers comfortable in getting started with PySpark along with its various
modules and submodules.
Prerequisites
Before proceeding with the various concepts given in this tutorial, it is being assumed that
the readers are already aware about what a programming language and a framework is.
In addition to this, it will be very helpful, if the readers have a sound knowledge of Apache
Spark, Apache Hadoop, Scala Programming Language, Hadoop Distributed File System
(HDFS) and Python.
CopyrightandDisclaimer
 Copyright 2017 by Tutorials Point (I) Pvt. Ltd.
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Pvt. Ltd. The user of this e-book is prohibited to reuse, retain, copy, distribute or republish
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of the publisher.
We strive to update the contents of our website and tutorials as timely and as precisely as
possible, however, the contents may contain inaccuracies or errors. Tutorials Point (I) Pvt.
Ltd. provides no guarantee regarding the accuracy, timeliness or completeness of our
website or its contents including this tutorial. If you discover any errors on our website or
in this tutorial, please notify us at contact@tutorialspoint.com

PySpark
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TableofContents
About the Tutorial ............................................................................................................................................i
Audience...........................................................................................................................................................i
Prerequisites.....................................................................................................................................................i
Copyright and Disclaimer .................................................................................................................................i
Table of Contents ............................................................................................................................................ ii
1. PySpark – Introduction .............................................................................................................................1
Spark – Overview.............................................................................................................................................1
PySpark – Overview.........................................................................................................................................1
2. PySpark – Environment Setup...................................................................................................................2
3. PySpark – SparkContext............................................................................................................................4
4. PySpark – RDD ..........................................................................................................................................8
5. PySpark – Broadcast & Accumulator.......................................................................................................14
6. PySpark – SparkConf...............................................................................................................................17
7. PySpark – SparkFiles ...............................................................................................................................18
8. PySpark – StorageLevel...........................................................................................................................19
9. PySpark – MLlib ......................................................................................................................................21
10. PySpark – Serializers ...............................................................................................................................24

PySpark
1
In this chapter, we will get ourselves acquainted with what Apache Spark is and how was
PySpark developed.
Spark–Overview
Apache Spark is a lightning fast real-time processing framework. It does in-memory
computations to analyze data in real-time. It came into picture as Apache Hadoop
MapReduce was performing batch processing only and lacked a real-time processing
feature. Hence, Apache Spark was introduced as it can perform stream processing in real-
time and can also take care of batch processing.
Apart from real-time and batch processing, Apache Spark supports interactive queries and
iterative algorithms also. Apache Spark has its own cluster manager, where it can host its
application. It leverages Apache Hadoop for both storage and processing. It uses HDFS
(Hadoop Distributed File system) for storage and it can run Spark applications on YARN
as well.
PySpark–Overview
Apache Spark is written in Scala programming language. To support Python with Spark,
Apache Spark Community released a tool, PySpark. Using PySpark, you can work with
RDDs in Python programming language also. It is because of a library called Py4j that
they are able to achieve this.
PySpark offers PySpark Shell which links the Python API to the spark core and initializes
the Spark context. Majority of data scientists and analytics experts today use Python
because of its rich library set. Integrating Python with Spark is a boon to them.
1.PySpark – Introduction

PySpark
2
In this chapter, we will understand the environment setup of PySpark.
Note: This is considering that you have Java and Scala installed on your computer.
Let us now download and set up PySpark with the following steps.
Step 1: Go to the official Apache Spark download page and download the latest version
of Apache Spark available there. In this tutorial, we are using spark-2.1.0-bin-
hadoop2.7.
Step 2: Now, extract the downloaded Spark tar file. By default, it will get downloaded in
Downloads directory.
# tar -xvf Downloads/spark-2.1.0-bin-hadoop2.7.tgz
It will create a directory spark-2.1.0-bin-hadoop2.7. Before starting PySpark, you need
to set the following environments to set the Spark path and the Py4j path.
export SPARK_HOME=/home/hadoop/spark-2.1.0-bin-hadoop2.7
export PATH=$PATH:/home/hadoop/spark-2.1.0-bin-hadoop2.7/bin
export PYTHONPATH=$SPARK_HOME/python:$SPARK_HOME/python/lib/py4j-0.10.4-
src.zip:$PYTHONPATH
export PATH=$SPARK_HOME/python:$PATH
Or, to set the above environments globally, put them in the .bashrc file. Then run the
following command for the environments to work.
# source .bashrc
Now that we have all the environments set, let us go to Spark directory and invoke PySpark
shell by running the following command:
# ./bin/pyspark
This will start your PySpark shell.
Python 2.7.12 (default, Nov 19 2016, 06:48:10)
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
Welcome to
____ __
/ __/__ ___ _____/ /__
2.PySpark – Environment Setup

PySpark
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_ / _ / _ `/ __/ '_/
/__ / .__/_,_/_/ /_/_ version 2.1.0
/_/
Using Python version 2.7.12 (default, Nov 19 2016 06:48:10)
SparkSession available as 'spark'.
>>>

PySpark
4
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