Book Image

Big Data Analysis with Python

By : Ivan Marin, Ankit Shukla, Sarang VK
Book Image

Big Data Analysis with Python

By: Ivan Marin, Ankit Shukla, Sarang VK

Overview of this book

Processing big data in real time is challenging due to scalability, information inconsistency, and fault tolerance. Big Data Analysis with Python teaches you how to use tools that can control this data avalanche for you. With this book, you'll learn practical techniques to aggregate data into useful dimensions for posterior analysis, extract statistical measurements, and transform datasets into features for other systems. The book begins with an introduction to data manipulation in Python using pandas. You'll then get familiar with statistical analysis and plotting techniques. With multiple hands-on activities in store, you'll be able to analyze data that is distributed on several computers by using Dask. As you progress, you'll study how to aggregate data for plots when the entire data cannot be accommodated in memory. You'll also explore Hadoop (HDFS and YARN), which will help you tackle larger datasets. The book also covers Spark and explains how it interacts with other tools. By the end of this book, you'll be able to bootstrap your own Python environment, process large files, and manipulate data to generate statistics, metrics, and graphs.
Table of Contents (11 chapters)
Big Data Analysis with Python
Preface

Missing Values


The data entries with no value assigned to them are called missing values. In the real world, encountering missing values in data is common. Values may be missing for a wide variety of reasons, such as non-responsiveness of the system/responder, data corruption, and partial deletion.

Some fields are more likely than other fields to contain missing values. For example, income data collected from surveys is likely to contain missing values, because of people not wanting to disclose their income.

Nevertheless, it is one of the major problems plaguing the data analytics world. Depending on the percentage of missing data, missing values may prove to be a significant challenge in data preparation and exploratory analysis. So, it's important to calculate the missing data percentage before getting started with data analysis.

In the following exercise, we will learn how to detect and calculate the number of missing value entries in PySpark DataFrames.

Exercise 38: Counting Missing Values...