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

Subsetting, Filtering, and Grouping


One of the most important aspects of data wrangling is to curate the data carefully from the deluge of streaming data that pours into an organization or business entity from various sources. Lots of data is not always a good thing; rather, data needs to be useful and of high-quality to be effectively used in downstream activities of a data science pipeline such as machine learning and predictive model building. Moreover, one data source can be used for multiple purposes and this often requires different subsets of data to be processed by a data wrangling module. This is then passed on to separate analytics modules.

For example, let's say you are doing data wrangling on US State level economic output. It is a fairly common scenario that one machine learning model may require data for large and populous states (such as California, Texas, and so on), while another model demands processed data for small and sparsely populated states (such as Montana or North...