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

Using REPL


Read-Eval-Print-Loop is an interactive shell or the language shell that provides the functionality to test out pieces of code. Julia provides an interactive shell with a Just-in-Time compiler at the backend. We can give inputs in a line, it is compiled and evaluated, and the result is given in the next line.

The benefit of using the REPL is that we can test out our code for possible errors. Also, it is a good environment for beginners. We can type in the expressions and press Enter to evaluate.

A Julia library, or custom-written Julia program, can be included in the REPL using include. For example, I have a file called hello.jl, which I will include in the REPL by doing the following:

julia> include ("hello.jl") 

Julia also stores all the commands written in the REPL in the .julia_history. This file is located at /home/$USER on Ubuntu, C:\Users\username on Windows, or ~/.julia_history on OS X.

As with a Linux Terminal, we can reverse-search using Ctrl + R in Julia's shell. This is a really nice feature as we can go back in the history of typed commands.

Typing ? in the language shell will change the prompt to:

help?>  

To clear the screen, press Ctrl + L. To come out of the REPL press Ctrl + D or type the following:

julia> exit().