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

Looking for patterns


Creating a good regular expression is a bit of a design process. A regular expression that is too rigid may not be able to match all of the potentially correct matches. On the other hand, a regular expression that is not specific enough may match a large number of strings incorrectly.

The key is to look for a well-defined pattern in the data that easily distinguishes the correct matches from otherwise incorrect matches. It is usually a helpful first step to look through the data itself. This allows you to get an intuitive sense for the existence and frequency of certain patterns.

The following python script uses pandas to read the dataset into a pandas dataframe, extract the address column, and print out a random sample of 100 addresses using the pandas series.sample() function. A random seed of 0 is used in order to make the resulting printout consistent. The script is available in the external resources as available in the external resources as explore_addresses.py.

import...