Book Image

Practical Data Wrangling

By : Allan Visochek
Book Image

Practical Data Wrangling

By: Allan Visochek

Overview of this book

Around 80% of time in data analysis is spent on cleaning and preparing data for analysis. This is, however, an important task, and is a prerequisite to the rest of the data analysis workflow, including visualization, analysis and reporting. Python and R are considered a popular choice of tool for data analysis, and have packages that can be best used to manipulate different kinds of data, as per your requirements. This book will show you the different data wrangling techniques, and how you can leverage the power of Python and R packages to implement them. You’ll start by understanding the data wrangling process and get a solid foundation to work with different types of data. You’ll work with different data structures and acquire and parse data from various locations. You’ll also see how to reshape the layout of data and manipulate, summarize, and join data sets. Finally, we conclude with a quick primer on accessing and processing data from databases, conducting data exploration, and storing and retrieving data quickly using databases. The book includes practical examples on each of these points using simple and real-world data sets to give you an easier understanding. By the end of the book, you’ll have a thorough understanding of all the data wrangling concepts and how to implement them in the best possible way.
Table of Contents (16 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Introducing the CSV module


The csv module is designed to process CSV data in an iterative manner. Rather than reading the data and then processing it, the csv module is designed to simultaneously read and process the data line by line.

This makes sense from an efficiency perspective. It takes less memory and less time to read and operate on the data entry by entry than it does to read the data as whole. For this reason, the csv module is well suited to process very large data files that are too big to read into memory.

Additionally, because the csv module is built-in, it will work with any Python installation, making it transferable. This is worth mentioning because it is a slight advantage of the csv module over the pandas module.

In the following exercise, I will demonstrate how to use the csv module to read and process data.