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

Refresher of RDBMS and SQL


An RDBMS is a piece of software that manages data (represented for the end user in a tabular form) on physical hard disks and is built using the Codd's relational model. Most of the databases that we encounter today are RDBMS. In recent years, there has been a huge industry shift toward a newer kind of database management system, called NoSQL (MongoDB, CouchDB, Riak, and so on). These systems, although in some aspects they follow some of the rules of RDBMS, in most cases reject or modify them.

How is an RDBMS Structured?

The RDBMS structure consists of three main elements, namely the storage engine, query engine, and log management. Here is a diagram that shows the structure of a RDBMS:

Figure 8.2 RDBMS structure

The following are the main concepts of any RDBMS structure:

  • Storage engine: This is the part of the RDBMS that is responsible for storing the data in an efficient way and also to give it back when asked for, in an efficient way. As an end user of the RDBMS...