KU-AICC202-Intro-to-Data-Science

Getting Started with Julia

Julia is an open source, high-level, strongly typed, dynamic, functional programming language designed for numerical analysis and computational science. Julia attempts to solve the “Two-Language” problem allowing to coding everything in a single language balancing both performance (as in C or Fortran) and productivity (as in Python). [Article: Why we create Julia]](https://julialang.org/blog/2012/02/why-we-created-julia/)

Setup

Please download Julia from https://julialang.org/downloads/ and follow the installation instructions presented at https://julialang.org/downloads/platform/. Install the current stable release.

Follow one of the following instructions to setup development environment

Visual Studio Code (https://code.visualstudio.com/)

• Download and install VS Code
• Start VS Code, click View->Command Palette… and type View: Show Extensions to go to the extension manager
• In the extension manager search and install “Julia Language Support” extension

Jupyter Notebook

• star console and type the following command

using Pkg
Pkg.add("IJulia")

using IJulia
IJulia.notebook(dir=".")

Pluto Notebook

using Pkg
Pkg.add("Pluto")

using Pluto
Pluto.run()

Using Julia REPL

• julia> : Julia REPL to interact with Julia Engine
• shell> : Enter through “;” for using shell command at REPL
  • Alternatively create and run command object

cmd = `echo hello` 
run(cmd)

• help> : Enter through “?” for using help, search through documentation
• (ENVNAME) pkg>: Entered through “]” for using Pkg.jl, Julia’s Package Manager, which activates the environment, and work with package registry, Alternatively import or use using Pkg
  • activate myEnv : creates and activates a new environment tracked by manifest file
  • Pkg.activate(; temp=true): create temp env will be deleted when the julia process is exited
  • add Distributions Plots : add packages, specify git repository URL to refer to unregistered packages
  • rm Distributions Plots: remove packages
  • update Plots: Update Packages
  • instantiate : Download all pacakges declared in Manifest.toml if it exists else resolve from Project.toml
  • Pkg.gc(; collect_delay::Period=Day(7), io::IO=stderr) #s weep over all known Manifest.toml and Artifacts.toml, makring “orphaned” artifacts and packages, and removing them if the pacakges are unsued for collect_delay period.
• (reverse-i-search) Enter through “^R” (Ctrl+R) for using previous commands matching a pattern
• forward-i-search
• Go to normal mode with BACKSPACE

Other common commands

• “^L” (Ctrl+L) clear screen
• “^D” (Ctrl+D) exit REPL
• “^C” (Ctrl+C) abort

; at the end of expression suppresses REPL output

One can access REPL through Julia cell in Jupyter Notebook as well

Reference

• Julia Language Manual
• MIT Introduction to Computational Thinking talks about CS, Maths Applications using Julia.

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