Getting Started with Julia in VS Code

A quick blog detailing how I created my first julia project.

This project was just first attempt creating a Julia Project using VS Code. Workflow is super important to me so I generally try to understand that first when learning a new language. I found the video by David Anthoff and decided to follow along and take notes along the way. This repository is the result. If you watch the video, he assumes you already have some familiarity with VS Code and glosses over certain keyboard shortcuts. I try my best to explicitly explain the steps below.

That being said, I assume you have already installed julia and the VS Code julia language extension. I also noticed that not all of the features worked for me as I followed along. I can only assume that there were some breaking changes in either the language, extension, or VS Code.

Creating an New Project

1. Within VS Code, pressing shift+cmd+p (control+shift+p on Windows) will open the command palette; after which type Julia: Start REPL to start a julia terminal
2. Within the REPL type ] to enter package mode, and activate . to activate a new environment
3. Type add DataFrames Query VegaLite VegaDatasets to add the desired project libraries
   • Notice there are now a Project.toml and Manifest.toml files in your directory which describe your requirements and dependencies respectively for this project
   • If you are working in a previously created project, you can call instantiate (which will use the existing Project.toml and Manifest.toml files) instead of add DataFrames ....
4. Now click on the Julia env: v1.x button in the status bar and select this directory as the environment. Your environment should update your directory’s name: Julia env: <your_dir_name>.
5. To get back to the Julia REPL, press backspace or ^C

Things to Know

1. To executed code interactively from the file into the terminal, use control+enter. This is different than in Python where users press shift+enter.
2. To restart the terminal, you can close the existing terminal by selecting the trash can or by shift+cmd+p and typing Julia: Stop REPL before creating a new one by shift+cmd+p and typing Julia: Start REPL. I did not find an easy way to restart the session.
3. Devcontainers are a great way to create an isolated environment. All you need is a .devcontainer folder with a devcontainer.json file. In this case we had the following simple code to direct the creation of a dev docker container:

{
    "image": "julia", 
    "extensions": ["julialang.language-julia"]
}

This tells VS Code to build a container and install using the julia image with the julialang VS Code extension. After the docker container is built, a user can activate . and instatiate to start working in the clean environment.