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

Handling non-standard CSV encoding and dialect


Most CSV data now is encoded using the standard Unicode formats that are used by default in Python. Occasionally however, you may come across a data file with an older or more obscure encoding format. In order to properly read and process data with a non-standard encoding, you will need to specify the encoding in the call to open() function that creates the file object. The pandas.read_csv() function also allows for the specification of non-standard encoding. I've made a link to the encoding formats accepted by Python in the Links and Further Reading document in the external resources.

There also may be variations in the delimiter, the character used to separate values, the newline character used to indicate the end of a line, and a few other formatting attributes. These variations are collectively referred to as the CSV dialect. Both the pandas.read_csv() function and the csv.reader() have parameters that allow you to specify variations in the...