Julia

Julia is a programming language that aims for easy coding while maintaining high speed, and it is ambitiously developed to replace languages like Fortran, MATLAB, Python, and R. As you can tell from the commonalities among these languages, Julia is gaining traction in scientific computing. Fresh Shrimp Sushi House, operating in the same field, also aims to popularize Julia in Korea.

Icon	Subcategory
	Features from Python
	Features from MATLAB
	Features from R
	Features unique to Julia

Here, “features unique to Julia” means characteristics that differentiate it from MATLAB, Python, and R. These may be common features in other programming languages. If you’re already familiar with these languages, the phrase “learning Julia” might sound odd. Many functions and expressions are similar, so knowing these languages is almost equivalent to knowing Julia. Refer to the post Equivalent Codes in Julia, MATLAB, Python, and R.

For information on how to perform machine learning in Julia, see the Machine Learning category.

Tutorial

Installation and Packages

• Julia Programming Language
  • Types and Annotations in Julia
• How to Install the Latest Version of Julia on Windows
  • How to Change the Number of Threads for Parallel Computing in Julia on Windows
  • How to Use Julia in Windows CMD and PowerShell
• How to Install the Latest Version of Julia on Linux
  • How to Change the Number of Threads for Parallel Computing in Julia on Linux
• How to Install and Use Packages Pkg.jl
  • Commands Available in Package Management Mode ]?
  • Fixing \\General\\Registry.toml: No such file or directory Error During Package Installation
  • How to Check Package Version status name
  • How to Install a Specific Version of a Package add foo@1.0
  • How to Load Packages from a List @eval using $(package)
• How to Use Functions Defined in Other Files include("file.jl")
• How to Clear the Console Ctrl + L, print("\033c")

I/O

• How to Read and Write *.mat Files MAT.jl
  • How to Save Data Like *.mat Files JLD2.jl
• How to Load *.npy Files PyCall.jl
• How to Read *.csv Files CSV.read()
  • How to Read Only Specific Columns from a *.csv File
  • How to Load DataFrames Without String7, String15 stringtype = String
• How to Output a 2D Array to a *.csv File CSV.write()
  • Fixing Garbled Characters When Outputting CSV CSV.write(bom = true)
• How to Read *.shp Files Shapefile.Table()
• How to Open a Dialog Box to Select Files Like file.choose() open_dialog()
• How to Load Built-in Datasets Used in R RDatasets.jl
• How to Use the Clipboard clipboard(), clipboard(x)
• How to Read Excel *.XLSX Files XLSX.jl

Basic Syntax

• How to Perform Random Sampling rand()
  • How to Fix Random Seed Random.seed!()
• Essential Julia Syntax: Broadcasting f.(x)
  • Broadcasting for Multivariate Functions
• Julia’s Powerful Convenience Feature, Macros @
  • How to Perform Parallel Processing @threads
  • How to Check the Executing Code File’s Location @__DIR__
  • How to Handle Exceptions error(), @error
• How to Use Greek Letters and Subscripts in Variable Names \alpha → α
• How to Use Elegant Loops while, for, zip()
  • How to Reference Index and Value Simultaneously in Loops enumerate()
• Symbols :foo
• Exclamation Mark Convention foo!()
• Comprehensions

Advanced Syntax

• Difference Between == and ===
• Lambda Expressions foo -> bar
• How to Use the Pipe Operator |>
• Ternary Operator ? :
  • Shortening Conditional Statements <condition> && <statement>
• How to Print Data Without Truncation show(stdout, "text/plain", foo)
• Metaprogramming Meta.parse(), eval()
• How to Execute External Programs run()
  • How to Pass Command Line Arguments ARGS
  • How to Reference Environment Variables Base.ENV
• How to Use Progress Bars ProgressMeter.jl, ProgressBars.jl
• How to Send Emails via Naver SMTPClient.jl
• How to Check the Operating System Sys.iswindows

Splat Operator ...

• Splat Operator ...
• How to Define Variadic Functions function f(x...)
• How to Convert Between 2D Arrays and Matrices [eachrow(M)...], hcat(A...)
• Tips for Passing Optional Arguments Using Julia’s Splat Operator foo(; args...)

Data Structures

• Array Slicing and Indexing x[1:end], x[[1,3,4]]
  • How to Reference Specific Positions in an Array Using Functions getindex(), first(), last()
• How to Check Struct Attributes propertynames()
  • How to Reference Struct Properties Using Functions getproperty()
  • How to Check Element Types Inside a Container eltype()
• Dictionaries and Pairs Dict(), x => y
  • How to Create a Dictionary from Arrays Dict(Key .=> Value)
  • How to Pass Multiple Keyword Arguments at Once Using a Dictionary
• Set Data Type and Operators Set
• Difference Between Vectors and Tuples
• Named Tuples (; x, y)
• How to Change the Default Data Type @changeprecision
• How to Convert Strings to Numbers parse(type, str)
• How to Remove Duplicates from a Collection unique(), allunique()

Arrays

• How to Create an Empty Array
  • How to Check if an Array is Empty isempty()
• How to Define an Array with a Specified Type
• Various Ways to Generate Vectors
  • How to Create an Array Filled with a Specific Value fill()
  • How to Flatten an Array vec()
• How to Directly Define High-Dimensional Vectors
  • Difference in Dimensions Between NumPy, PyTorch Arrays
  • Functions Related to 2D Array Operations
    • How to Perform Element-wise Operations on Two Vectors of Different Sizes
    • How to Perform Row-wise and Column-wise Scalar Multiplication d .* X, X .* d'
    • How to Normalize a Matrix Column-wise X ./ norm.(eachcol(X))'
  • How to Create an N-Dimensional Grid
• How to Compute Arrays Column-wise
• How to Shift Arrays circshift()
  • How to Use Circular Arrays circshift()
  • How to Compute Differences in Arrays diff()
• Multidimensional Indices CartesianIndex
  • Functions to Find Indices findall(), findfirst(), findnext(), argmax()
  • How to Check if Array Elements Belong to a List in Ref()
• Function to Access Elements in a Singleton Set only
• Sorting Permutation Functions and Their Applications sortperm
• Categorical Arrays CategoricalArrays.jl
• Named Arrays NamedArrays.jl

Strings

• How to Concatenate Strings *, string(), join(), ^
  • How to Slice Only Part of a Unicode String
• How to Conveniently Print Variable Values Using Interpolation $string
• How to Manipulate Strings Like in Python replace(, "a" => "A"), join(), split()
  • How to Use Python’s zfill() lpad()
• How to Find Specific Pattern Positions in a String findfirst(), findnext(), findlast()
  • How to Check if a String Contains a Specific Substring contains(Ref, Query)
• Built-in Functions to Style Text Output printstyled()
  • Package for Styling Text Output Crayons.jl

DataFrames DataFrames.jl

• How to Create an Empty DataFrame
  • How to Add New Rows vcat(), push!()
  • How to Add New Columns df[!, :"column_name"]
• How to Convert Between DataFrames and 2D Arrays Array(df), DataFrame(array, :auto)
• How to Create a DataFrame with Variable Names as Column Names DataFrame(; x, y)
  • How to Sort a DataFrame by Columns sort(df,:colname)
  • How to Exclude Specific Columns from a DataFrame Not(:colname)
  • How to Rename Columns in a DataFrame rename!(, :x => :y)
• How to Summarize a DataFrame describe()
  • How to Check the Size of a DataFrame nrow(), ncol()
• How to Modify Specific Values in a DataFrame replace!(df, A=>B)
  • How to Remove Duplicate Rows unique(df,:colname)
  • How to Replace NaN with 0 in a DataFrame
  • How to Remove Missing Values from a DataFrame dropmissing()
• How to Split and Compute DataFrames by Group groupby(), combine()
• How to View DataFrames Neatly in VSCode Main.VSCodeServer.vscodedisplay(df)

Images Images.jl

• How to Rotate Image Arrays imrotate()
• How to Resize Images imresize()
• How to Load Images and Convert Them to Matrices convert(Array{Float64},)
• How to Flip Images Vertically and Horizontally rotr90(img')

Visualization

• List of Plot Properties
• How to Set Figure Size and Resolution size=(w,h), dpi=
• How to Create Animations @animate
• How to Create Plot Themes RecipesBase.jl
• How to Change Default Plot Settings default()
• How to Output Simple Plots in the Console UnicodePlots.jl
• How to Adjust Camera Angles in 3D Plots camera=(azimuth, elevation)

Rendering

• How to Add Lines to Plots plot!(xs, ys)
  • How to Add Vertical and Horizontal Lines vline!(), hline!()
  • How to Draw Arrows plot!([x1, x2], [y1, y2], arrow=true)
• How to Output Plots with Transparent Backgrounds background_color = :transparent
• How to Adjust Aspect Ratios ratio = :equal
• How to Fill Areas Up to Specific Values/Between Two Curves/Inside Closed Curves fill=()
• How to Plot Vector Fields quiver(, quiver=)

Text

• How to Add Text to Plots annotate!()
• How to Use $\TeX$ in Plots LaTexStrings.jl, L"$f(x)$"
• How to Add Korean Text to Plots default(fontfamily = ""), Plots.plotly()
• How to Adjust Legend Positions legend = :topbottom
  • How to Hide Labels for Specific Data in Plots label = ""

Style

• How to Share Axes with Different Scales in Plots twinx(), twiny()
• How to Style Grid Lines in Plot Backgrounds
• How to Change Axis Styles framestyle
  • How to Output Plots Cleanly by Removing Axes and Ticks framestyle=:none
  • How to Remove Only Axis Values formatter = (_...) -> ""
  • How to Swap X and Y Axes permute = (:y, :x)
• List of Marker and Line Styles plot(shape=, linestyle=)
  • How to Add Colors to Markers in Scatter Plots scatter(marker_z=), scatter(group=)
• How to Draw Regression Lines in Scatter Plots scatter(smooth = true)
• How to Use Pi Symbols on Axes xtick = ([π, 2π], ["π", "2π"])

Color

• How to Use Colors
• How to Use Palettes
• How to Use Color Gradients
• Package for Color Processing Colors.jl
  • How to Use RGB Codes RGB(1, 0, 0)
  • How to Use HEX Codes "#000000"
• How to Specify Colors for Graph Elements
  • How to Specify Graph Colors in Subplots
• How to Specify Colors for Axes, Axis Labels, Ticks, and Tick Labels
• How to Specify Background Colors
• How to Get Colors from a Color Scheme Using Values Between 0 and 1 get(colorschemes[:plasma], 1.0)

Layout

• How to Create Subplots Using Layouts layout = (n,m)
• How to Add a Main Title to Subplots plot_title = ""

Heatmaps

• How to Specify Color Ranges in Heatmaps clim = (,)
• How to Output and Save Arrays as Heatmap Images
• How to Overlay Plots on Heatmaps

StatsPlots.jl

• How to Draw Dendrograms
• Macro to Omit DataFrame Names @df
• How to Draw Box Plots boxplot(data, labels="label")

Mathematics

You can find Graphs.jl, a package related to Graphs (Networks), in the Graph Theory category.

Computation

• How to Perform Random Sampling with Weights sample(, Weights())
  • How to Sample from a Given Distribution rand(distribution, )
• How to Round to Specific Decimal Places round(digits=)
• How to Invert Bit Arrays .!(foo)
• How to Count Frequencies freqtable()
• How to Use Date and Time Functions Dates
  • How to Calculate the Difference Between Two Times in Hours, Minutes, Seconds Dates.canonicalize()
• How to Use Composite Functions ∘
• How to Use Infinity ∞
• How to Check Approximate Equality ≈
• How to Use Complex Numbers im
• How to Compute the Mean Excluding Zeros or Missing Values mean(!iszero,)
• Difference Between Inf and NaN When Dividing by Zero
• Comparison of NaN Values
• 🔒 How to Perform Distributed Computing @distributed

Libraries

• Linear Algebra Module LinearAlgebra
• Polynomial Functions Package Polynomial.jl
• Number Theory Package Primes.jl
• Differential Calculus Package Calculus.jl
  • Automatic Differentiation Package Zygote.jl
• How to Compute Distance Matrices Distances.jl
• Symbolic Computation Package Symbolics.jl
  • How to Use Symbolic Computation SymEngine.jl
• How to Perform Regression Analysis GLM.jl
• Fourier Transform Package FFTW.jl
• How to Use Infinite Arrays InfiniteArrays.jl
• How to Perform Numerical Interpolation Interpolations.jl
• How to Use Finite Differences FiniteDifferences.jl
• Clustering Package Clustering.jl
  • $K$-Means Clustering kmeans()
  • Hierarchical Clustering hclust()
• How to Use Decision Trees DecisionTree.jl
• Natural Language Processing Package TextAnalysis.jl

Code Optimization Techniques

• Performance Comparison of == Operator with Characters and Integers
• How to Optimize Distance Matrix Computations pairwise()
  • How to Compute Distances Quickly Using k-d Trees NearestNeighbors.jl
• How to Truncate Decimal Places and Convert to Integers trunc()
• How to Reference Subarrays Quickly @views
• Short-Circuit Evaluation &&, ||

Looking for Features Not Listed?

If you can’t find what you’re looking for in the posts, you might find it in the list below.

• Community
  • Fresh Shrimp Sushi House Community 💬: The only Korean-language Julia community.
    • Julia Users Open KakaoTalk Chat
  • Practical First Steps in Julia: Introduces several problems to help you get familiar with the basics of Julia.
    • Practice Problems for Practical First Steps in Julia
    • Advanced Course in Practical Julia: Learn about packages.
• Books
  • First Semester in Numerical Analysis with Julia: Covers basic content in numerical analysis and how to implement it in Julia. You can download the PDF from the link.
  • Julia Data Science: An online book released in November 2021. Available in English, Portuguese, and Chinese. Mainly covers DataFrames.jl and the visualization package Makie.jl. You can download the PDF from the link.
  • Algorithm for Optimization: Contains various methods for solving optimization problems and how to implement them in Julia. You can download the original or chapter PDFs from the link. A Korean translation titled Practical Optimization Algorithms (Understanding Optimization Algorithm Solutions with Julia) has been published in Korea.
• Packages
  • JuliaDB.jl: A data processing library boasting high speed and memory management.
  • Metatheory.jl: A library for metaprogramming and symbolic computation.
  • Cairo.jl: A package offering powerful image creation capabilities. It differs from general visualization tools.
• Miscellaneous
  • Profiler: Provides performance profiling similar to MATLAB.
  • The Fast Track to Julia: A concise table summarizing Julia syntax.
  • Julia?: A blog run by an individual who shares many advanced tips on using Julia.