Learning Julia

Thought I would try something a bit different and take a break from the project I’ve been working the past few weeks.

I decided to spend 90 minutes to learn a bit about the Julia Programming Language

Setup

To setup my dev environment, I used asdf with the asdf-julia plugin.

asdf plugin-add julia https://github.com/rkyleg/asdf-julia.git
asdf install julia 1.6.1
asdf global julia 1.6.1

Impressions

• It’s very strong for numerical computation
• Feels influenced by C, R, ruby, javascript
• Lots of nice syntax, for example a fraction can be represented as 2//8, and it will simplify it to 1//4, and then you can turn it back to a float float(2//8) == 0.25
• Comprehensions are very clean [(j, i) for i=1:3 for j=1:3 if j==i]
• It types the arrays for you typeof([1,2,3]) == Vector{Int64} while typeof(["a", "b", "c"]) == Vector{String}, and if types are mixed, it uses Vector{Any}
• The type system is great. Infered types.
• Matrix is easy to use:

julia> [1:3 5:7]
3×2 Matrix{Int64}:
 1  5
 2  6
 3  7

• Null is called missing
• Terse syntax is available for functions: f(x,y) = x + y
• Operators are functions:

julia> 1 + 2 + 3
6

julia> +(1,2,3)
6

julia> f = +;

julia> f(1,2,3)
6

• Ranges of cells can be updated using the dot syntax: arr[2:7] .= 99
• Tuples can be either named or unamed

julia> (2, 1+2)
(2, 3)

julia> (a=2, b=1+2)
(a = 2, b = 3)

• Functions can be composed:

julia> (sqrt ∘ +)(3, 6)
3.0

• Functions can be piped:

julia> 1:10 |> sum |> sqrt
7.416198487095663

julia> (sqrt ∘ sum)(1:10)
7.416198487095663