Getting Started

Julia installation is straightforward, whether using precompiled binaries or compiling from source. Download and install Julia by following the instructions at https://julialang.org/downloads/.

If you are coming to Julia from one of the following languages, then you should start by reading the section on noteworthy differences from MATLAB, R, Python, C/C++ or Common Lisp. This will help you avoid some common pitfalls since Julia differs from those languages in many subtle ways.

The easiest way to learn and experiment with Julia is by starting an interactive session (also known as a read-eval-print loop or "REPL") by double-clicking the Julia executable or running julia from the command line:

$ julia

               _
   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.11.2 (2024-12-01)
 _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org/ release
|__/                   |


julia> 1 + 2
3

julia> ans
3

To exit the interactive session, type CTRL-D (press the Control/^ key together with the d key), or type exit(). When run in interactive mode, julia displays a banner and prompts the user for input. Once the user has entered a complete expression, such as 1 + 2, and hits enter, the interactive session evaluates the expression and shows its value. If an expression is entered into an interactive session with a trailing semicolon, its value is not shown. The variable ans is bound to the value of the last evaluated expression whether it is shown or not. The ans variable is only bound in interactive sessions, not when Julia code is run in other ways.

To evaluate expressions written in a source file file.jl, write include("file.jl").

To run code in a file non-interactively, you can give it as the first argument to the julia command:

$ julia script.jl

You can pass additional arguments to Julia, and to your program script.jl. A detailed list of all the available options can be found under Command-line Interface.

Resources

A curated list of useful learning resources to help new users get started can be found on the learning page of the main Julia website.

You can use the REPL as a learning resource by switching into the help mode. Switch to help mode by pressing ? at an empty julia> prompt, before typing anything else. Typing a keyword in help mode will fetch the documentation for it, along with examples. Similarly for most functions or other objects you might encounter!

help?> begin
search: begin disable_sigint reenable_sigint

  begin

  begin...end denotes a block of code.

If you already know Julia a bit, you might want to peek ahead at Performance Tips and Workflow Tips.