Book Image

Julia for Data Science

By : Anshul Joshi
2 (1)
Book Image

Julia for Data Science

2 (1)
By: Anshul Joshi

Overview of this book

Julia is a fast and high performing language that's perfectly suited to data science with a mature package ecosystem and is now feature complete. It is a good tool for a data science practitioner. There was a famous post at Harvard Business Review that Data Scientist is the sexiest job of the 21st century. (https://hbr.org/2012/10/data-scientist-the-sexiest-job-of-the-21st-century). This book will help you get familiarised with Julia's rich ecosystem, which is continuously evolving, allowing you to stay on top of your game. This book contains the essentials of data science and gives a high-level overview of advanced statistics and techniques. You will dive in and will work on generating insights by performing inferential statistics, and will reveal hidden patterns and trends using data mining. This has the practical coverage of statistics and machine learning. You will develop knowledge to build statistical models and machine learning systems in Julia with attractive visualizations. You will then delve into the world of Deep learning in Julia and will understand the framework, Mocha.jl with which you can create artificial neural networks and implement deep learning. This book addresses the challenges of real-world data science problems, including data cleaning, data preparation, inferential statistics, statistical modeling, building high-performance machine learning systems and creating effective visualizations using Julia.
Table of Contents (17 chapters)
Julia for Data Science
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface

Inferring column types


To understand the dataset and move any further, we need to first understand what type of data we have. As our data is stored in columns, we should know their type before performing any operations. This is also called creating a data dictionary:

julia> typeof(iris_dataframe[1,:SepalLength]) 
Float64 
 
julia> typeof(iris_dataframe[1,:Species]) 
ASCIIString 

We have used the classic dataset of iris here. We already know the type of the data in these columns. We can apply the same function to any similar dataset. Suppose we were only given columns without labels; then it would have been hard to determine the type of data these columns contain. Sometimes, the dataset looks as if it contains numeric digits but their data type is ASCIIString. These can lead to errors in further steps. These errors are avoidable.