1. How to Create a Julia Project

Julia uses the built-in Pkg package manager to organize projects and dependencies. It is recommended to use an isolated environment for each project so that you can avoid package conflicts and keep the environment reproducible. This article explains how to create and use a Julia project.

The code in this article was tested with Julia 1.12.1.

1. Initialize a Julia project (generate)

Enter the Julia REPL and run:

using Pkg
Pkg.generate("MyPackage")

Or press ] to switch from the julia> prompt to pkg>, then run:

generate MyPackage

The two forms above are equivalent.

This generates:

Generating  project MyPackage:
    MyPackage\Project.toml
    MyPackage\src\MyPackage.jl

• The MyPackage folder
• MyPackage\Project.toml: records dependency names and compatibility ranges
• MyPackage\src\MyPackage.jl: example package source code
• Manifest.toml: records all dependencies and exact versions to make the environment reproducible

Now switch to the newly created project folder:

cd MyPackage

2. Activate the project (activate)

Inside the project folder, press ] to enter pkg> mode and run:

activate .

This activates the current folder as a Julia project. You should see the project name appear in the prompt. At that point the project is active.

3. Add dependencies

Add dependencies as usual. For example:

using Pkg
Pkg.add("Plots")
Pkg.add("DataFrames")

The dependencies will be written into Project.toml, and Manifest.toml will also be updated. If this is the first dependency added to the project, Manifest.toml will be created automatically.

4. Remove dependencies

Removing a package in Julia is straightforward. You can use Pkg.rm() or use rm package_name in Pkg mode.

For example, to remove Plots:

Pkg.rm("Plots")

Julia will automatically update both Project.toml and Manifest.toml.

5. Basic project structure

MyPackage/
│
├── src/
│   └── MyPackage.jl
│
├── Project.toml
└── Manifest.toml

2. How Others Install Dependencies After Cloning Your Project

If someone clones your project with Git:

git clone https://github.com/yourname/MyPackage.git
cd MyPackage

Then in the Julia REPL:

using Pkg
Pkg.activate(".")
Pkg.instantiate()

Pkg.instantiate() installs every dependency and exact version according to Project.toml and Manifest.toml, ensuring the environment matches yours.

3. Summary of Common Commands

• generate MyPackage: create a new project
• activate .: activate the current project
• add PackageName: add a dependency
• rm PackageName: remove a dependency
• instantiate: install all dependencies listed in the project files

贡献者: Junyuan He