Julia - Installation Instructions
In this course, you will learn a bit about the Julia programming language. This means that you will need to install:
1. The programming language, Julia.
2. A programming environment, Visual Studio Code or Atom, along with the proper extensions for the Julia programming language.
This page contains the instructions for the required installations as well as some beginner tips on how to use either programming environment.
1. Installing the Julia programming language
First, install Julia: https://julialang.org/downloads/
More specifically, use the 1.7.2 version for the operating system of your preference (I will be using Windows 64-bit).
We recommend that you accept the default installation options.
2. Installing the Programming Environment
OPTION A: Installing Visual Studio Code
Install Visual Studio Code: https://code.visualstudio.com/
More specifically, use: https://code.visualstudio.com/Download#
We recommend that you accept the default installation options.
Installing the Julia Extension
Launch Visual Studio Code and install the Julia extension.
In Visual Studio Code, click the View menu in the top bar, and choose Extensions (Ctrl+Shift+X).
In the extensions pane, type Julia into the search engine (on top) and select the Julia extension by clicking the install button. Visual Studio Code will install it. When the installation completes, restart Visual Studio Code.
Launching the Terminal and the Julia REPL
To run code, or to visualize the results of any program you run, you must launch the Terminal (or REPL). If this tab is not already visible at the bottom of your workspace, go to the View menu in the top bar and choose Terminal (Ctrl+ç in a PT keyboard; Ctrl+` in a US keyboard).
The terminal, at the bottom of your screen, should indicate that you are running Julia. If you do not see a Julia prompt in your terminal (julia>), change the dropdown menu on the top right corner of the terminal to the Julia REPL option.
Another option to start the Julia REPL is available directly through the Command Pallete. Go to the View menu in the top bar and choose Command Pallete (Ctrl+Shift+P). Type Julia: Start REPL in the search engine that appears and select the corresponding option. The terminal should appear at the bottom of your workspace. The same can be achieved with the following key bindings: Alt+J Alt+O
OPTION B: Installing Atom
Install Atom: https://atom.io/
More specifically, use: https://atom.io/download/windows_x64
We recommend that you accept the default installation options.
Install the Juno extension
Launch Atom and install Juno.
In Atom, either choose Install Package in the list of options that appear or go to Settings (Ctrl+,) and go to the Install panel. Type uber-juno into the search box and hit Enter. Click the Install button on the package of the same name and wait. Atom will install several packages and will inform you when it's done. You can answer Yes to all questions presented by Atom.
Opening the Julia REPL
When the installation completes, you will have a pane at the bottom (REPL) for interacting with Julia. If the REPL does not show, go to the Juno menu in the top bar and choose Open REPL (Ctrl+J Ctrl+O). Alternatively, use the new Juno tab, which should have appeared at the left of your workspace after the Juno installation. Find the REPL icon in the tab and click on it. The icon resembles a rectangular screen with the symbols >_ on it.
Julia - Beginner tips
OPTION A: Visual Studio Code
Opening a Julia file
You can write and run programs directly in the Julia REPL. However, these cannot be saved for later use. The REPL is useful for testing parts of your program and for visualizing the results of program runs. For more complex developments, you should work on a Julia file that can be saved to your computer.
To begin programming, open a new text file. Go to the File menu in the top bar and choose New File (Ctrl+N). This will open a new text file. You now have two options to convert it into a Julia file:
A. On the bottom right corner of the workspace, you will notice the file is cataloged as Plain Text in the Select Language Mode button. Click on it to change the file type. A search engine will appear, where you should write and select Julia. Your file should now be recognized as a Julia file.
B. The same effect can be achieved by saving the new text file with the Julia extension. Select the File menu in the top bar and choose Save As (Ctrl+Shift+S). In the Save as type dropdown menu select the Julia (*.jl) option, or simply add the extension yourself to the file name (e.g. Untitled.jl).
You can now start developing Julia code within the file.
Running Code
There are several options to run the code in your program. You may run the full program, or you may prefer to run only parts of it. In either case, the results of each run will show in the Julia REPL.
To run the full program click Shift+Enter when your cursor is anywhere within the program file.
To run only parts of the file, you can use Ctrl+Enter, which sends the current line (where your cursor is) or selection to the REPL, or use Alt+Enter, which runs the current instruction and moves your cursor downwards simultaneously.
Other useful commands include:
Ctrl+D or Alt+J Alt+K for exiting the Julia REPL
Ctrl+C to interrupt or cancel a process. Useful to break infinite loops or erroneous runs.
Ctrl+L to clear terminal screen.
Inline visualization of results
We have shown you how to visualize program results in the REPL. There are other options for the visualization of results, namely inline visualization, which allows you to see the results of your program directly in the program file, in front of the line you just ran. Go to the File menu in the top bar, choose Preferences, and then Settings (Ctrl+,). Here open the Extensions drop-down menu and find Julia. In the Julia extension settings menu, change the default options in Execution: Result Type to inline or to both.
OPTION B: Atom
Opening a Julia file
As you have seen, you can write and run programs directly in the Julia REPL. However, these instructions cannot be saved for later use. The REPL is useful for testing parts of your program and for visualizing the results of program runs. For more complex developments, you should work on a Julia file that can be saved to your computer.
To begin programming, open a new text file. Go to the Juno menu in the top bar and choose New Julia File. Alternatively, click on the New Julia File icon on the Juno pane to the left of your workspace. The icon resembles a sheet of paper with the symbols </> on it. You can now start developing Julia code within the file.
Note that Atom offers you a blank file (untitled) to start with, or you can also open another one in the File menu, with the option New File (Ctrl+N). These files, however, are not Julia files. If you started developing a program in such a file and wish to convert it to Julia, save it as a Julia file on your computer. Select the File menu in the top bar and choose Save As (Ctrl+Shift+S). The Julia extension will not show in the Save as type dropdown menu. Hence, you must add the extension (*.jl) yourself to the file name (e.g. Untitled.jl).
Running Code
There are several options to run the code in your program. You may run the full program, or you may prefer to run only parts of it.
To run the full program, use the Run all (Ctrl+Shift+Enter) option in the Juno pane or the Juno menu. In the Juno pane, the icon resembles a triangle. The results of your program will be shown in the REPL.
To run parts of the program, use the Run Block option (Shift +Enter) in the Juno pane or the Juno menu. In the Juno pane, the icon resembles a lightning bolt. This action will cause the evaluation of the current line (where your cursor is) or selection. The result of each instruction will appear inline in the program file.
Other useful actions include:
Interrupt Julia (Ctrl+Shift+C) interrupts or cancels a process. It is useful to break infinite loops or erroneous runs. In the Juno pane, the icon resembles a pause symbol.
Strop Julia (Ctrl+J Ctrl+K) for exiting the Julia REPL. In the Juno pane, the icon resembles a stop symbol, a square with rounded corners.
In the Juno menu, there is also an option for cleaning the REPL history. Click on Clear REPL (Ctrl+L or Ctrl+J Ctrl +C).