Book Image

Data Wrangling with Python

By : Dr. Tirthajyoti Sarkar, Shubhadeep Roychowdhury
Book Image

Data Wrangling with Python

By: Dr. Tirthajyoti Sarkar, Shubhadeep Roychowdhury

Overview of this book

For data to be useful and meaningful, it must be curated and refined. Data Wrangling with Python teaches you the core ideas behind these processes and equips you with knowledge of the most popular tools and techniques in the domain. The book starts with the absolute basics of Python, focusing mainly on data structures. It then delves into the fundamental tools of data wrangling like NumPy and Pandas libraries. You'll explore useful insights into why you should stay away from traditional ways of data cleaning, as done in other languages, and take advantage of the specialized pre-built routines in Python. This combination of Python tips and tricks will also demonstrate how to use the same Python backend and extract/transform data from an array of sources including the Internet, large database vaults, and Excel financial tables. To help you prepare for more challenging scenarios, you'll cover how to handle missing or wrong data, and reformat it based on the requirements from the downstream analytics tool. The book will further help you grasp concepts through real-world examples and datasets. By the end of this book, you will be confident in using a diverse array of sources to extract, clean, transform, and format your data efficiently.
Table of Contents (12 chapters)
Data Wrangling with Python
Preface
Appendix

Summary


In this topic, we looked at the structure of an HTML document. HTML documents are the cornerstone of the World Wide Web and, given the amount of data that's contained on it, we can easily infer the importance of HTML as a data source.

We learned about bs4 (BeautifulSoup4), a Python library that gives us Pythonic ways to read and query HTML documents. We used bs4 to load an HTML document and also explored several different ways to navigate the loaded document. We also got necessary information about the difference between all of these methods.

We looked at how we can create a pandas DataFrame from an HTML document (which contains a table). Although there are some built-in ways to do this job in pandas, they fail as soon as the target table is encoded inside a complex hierarchy of elements. So, the knowledge we gathered in this topic by transforming an HTML table into a pandas DataFrame in a step-by-step manner is invaluable.

Finally, we looked at how we can create a stack in our code...