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

Compound statements


So far, each line of code that you have written gets executed exactly once and immediately after it is written. Compound statements are Python structures that allow you to control when and how certain pieces of code get executed. Compound statements significantly increase your expressiveness as a programmer. In other words, they allow you to do more with less code. Before introducing a few compound statements, it will be helpful to go over the syntactical structure.

Compound statement syntax and indentation level

A compound statement consists of two parts. The first part, the clause header, is a line containing the type of statement and some other information specific to the statement. The clause header always starts with the type of clause and ends with a colon. The following is the syntax of a clause header:

<clause type> <clause body>:

(Note that this figure and the next two are just to demonstrate the syntactical structure and do not represent functional code...