Book Image

Julia 1.0 Programming Complete Reference Guide

By : Ivo Balbaert, Adrian Salceanu
Book Image

Julia 1.0 Programming Complete Reference Guide

By: Ivo Balbaert, Adrian Salceanu

Overview of this book

Julia offers the high productivity and ease of use of Python and R with the lightning-fast speed of C++. There’s never been a better time to learn this language, thanks to its large-scale adoption across a wide range of domains, including fintech, biotech and artificial intelligence (AI). You will begin by learning how to set up a running Julia platform, before exploring its various built-in types. This Learning Path walks you through two important collection types: arrays and matrices. You’ll be taken through how type conversions and promotions work, and in further chapters you'll study how Julia interacts with operating systems and other languages. You’ll also learn about the use of macros, what makes Julia suitable for numerical and scientific computing, and how to run external programs. Once you have grasped the basics, this Learning Path goes on to how to analyze the Iris dataset using DataFrames. While building a web scraper and a web app, you’ll explore the use of functions, methods, and multiple dispatches. In the final chapters, you'll delve into machine learning, where you'll build a book recommender system. By the end of this Learning Path, you’ll be well versed with Julia and have the skills you need to leverage its high speed and efficiency for your applications. This Learning Path includes content from the following Packt products: • Julia 1.0 Programming - Second Edition by Ivo Balbaert • Julia Programming Projects by Adrian Salceanu
Table of Contents (18 chapters)

Running shell commands

To interact with the operating system from within the Julia REPL, there are a few helper functions available, as follows:

  • pwd(): this function prints the current directory, for example, "d:\\test"
  • cd("d:\\test\\week1"): this function helps to navigate to subdirectories
  • ;in the interactive shell, you can also use shell mode using the ; modifier, for example: ; cd folder: navigates to folder

However, what if you want to run a shell command by using the operating system (the OS)? Julia offers efficient shell integration through the run function, which takes an object of type Cmd, defined by enclosing a command string in backticks (``).

The following are some examples for Linux or macOS X (at the time of writing: September 2018):

# Code in Chapter 9\shell.jl: 
cmd = `echo Julia is smart` 
   typeof(cmd) #> Cmd  
   run...