Book Image

Using OpenRefine

Book Image

Using OpenRefine

Overview of this book

Data today is like gold - but how can you manage your most valuable assets? Managing large datasets used to be a task for specialists, but the game has changed - data analysis is an open playing field. Messy data is now in your hands! With OpenRefine the task is a little easier, as it provides you with the necessary tools for cleaning and presenting even the most complex data. Once it's clean, that's when you can start finding value. Using OpenRefine takes you on a practical and actionable through this popular data transformation tool. Packed with cookbook style recipes that will help you properly get to grips with data, this book is an accessible tutorial for anyone that wants to maximize the value of their data. This book will teach you all the necessary skills to handle any large dataset and to turn it into high-quality data for the Web. After you learn how to analyze data and spot issues, we'll see how we can solve them to obtain a clean dataset. Messy and inconsistent data is recovered through advanced techniques such as automated clustering. We'll then show extract links from keyword and full-text fields using reconciliation and named-entity extraction. Using OpenRefine is more than a manual: it's a guide stuffed with tips and tricks to get the best out of your data.
Table of Contents (13 chapters)
Using OpenRefine
Credits
Foreword
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Recipe 5 – adding derived columns


Sometimes you do want to transform the contents of a cell, but also keep the original value. While you can go back to a cell's previous state using the Undo / Redo tab if something went wrong, it could be useful to see both the original value and the transformed value at the same time. Therefore, OpenRefine enables you to add a column based on another one.

Suppose we want to have a separate field that counts the number of categories per record. Click on the Categories dropdown, click on Edit column and Add column based on this column… A dialog very similar to the cell transformation dialog pops up; however, this time it additionally asks for a column name. Enter Category Count into the New column name field. Now, we have to create the expression that will count the number of categories. Since all categories are separated by a character (a vertical bar, or a comma if you followed the last recipe), we can simply split them and count the number of segments....