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

Opening and closing a file in Python using file I/O


In order to gain access to a file, a computer program needs to interact with the operating system; the process is called file I/O. File I/O is the way in which a programming language is able to open, read from, write to, and close files. (The I/O here stands for input/output, because the program takes input from certain files and writes output to other files.)

Note

While it is not always necessary to explicitly open a file, it is important to conceptually separate the process of opening a file from the process of reading the contents of a file. This is because it is often necessary to read the contents of a file incrementally or specify particular parameters when the file is opened.

In the following subsection, I will show to use python to open a file.

The open function and file objects

To open a file, you can use Python's built-in open() function:

file = open("<relative/path/to/file>", "<permission>")

The variable named file in the...