Book Image

Python Data Visualization Cookbook (Second Edition)

Book Image

Python Data Visualization Cookbook (Second Edition)

Overview of this book

Python Data Visualization Cookbook will progress the reader from the point of installing and setting up a Python environment for data manipulation and visualization all the way to 3D animations using Python libraries. Readers will benefit from over 60 precise and reproducible recipes that will guide the reader towards a better understanding of data concepts and the building blocks for subsequent and sometimes more advanced concepts. Python Data Visualization Cookbook starts by showing how to set up matplotlib and the related libraries that are required for most parts of the book, before moving on to discuss some of the lesser-used diagrams and charts such as Gantt Charts or Sankey diagrams. Initially it uses simple plots and charts to more advanced ones, to make it easy to understand for readers. As the readers will go through the book, they will get to know about the 3D diagrams and animations. Maps are irreplaceable for displaying geo-spatial data, so this book will also show how to build them. In the last chapter, it includes explanation on how to incorporate matplotlib into different environments, such as a writing system, LaTeX, or how to create Gantt charts using Python.
Table of Contents (16 chapters)
Python Data Visualization Cookbook Second Edition
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Importing data from fixed-width data files


Log files from events and time series data files are common sources for data visualizations. Sometimes, we can read them using CSV dialect for tab-separated data, but sometimes they are not separated by any specific character. Instead, fields are of fixed widths and we can infer the format to match and extract data.

One way to approach this is to read a file line by line and then use string manipulation functions to split a string into separate parts. This approach seems straightforward, and if performance is not an issue, it should be tried first.

If performance is more important or the file to parse is large (hundreds of megabytes), using the Python module struct (http://docs.python.org/library/struct.html) can speed us up as the module is implemented in C rather than in Python.

Getting ready

As the module struct is part of the Python Standard Library, we don't need to install any additional software to implement this recipe.

How to do it...

We will...