Would it be fun to have a thread where people share really fancy one liners? I think so - I think it’d be a great way to show off some of Julia to newcomers but also share some cool code. I’ll kick the thread off with 2-3, """ SquareEuclideanDistance(X) Returns the squared Grahm aka the euclide…

[image] Mason: However, julia gives not guarantees that inference will run exactly so future minor releases could make this less reliable, but that is unlikely since identity is quite easy to infer There is nothing in that code that semantically depend on inference. That would be very bad (fo…

[image] kristoffer.carlsson: There is nothing in that code that semantically depend on inference. That would be very bad (for the reason you mentioned). Right, so if I run a = [var1, var2, var3], I’m not actually very clear on what algorithm julia uses to decide on the appropriate eltype of a.…

[image] Mason: I’m not actually very clear on what algorithm julia uses to decide on the appropriate eltype of a . It accumulates into an array of the narrowest element type and when it encounters an element with another type, it widens the type, creates a new array, copies over all elements …

If you enjoy this sort of thing and know a bit of Python, you might find this talk I saw at PyCon 2016 about the “onelinerizer” amusing: Chelsea Voss - Oneliner-izer: An Exercise in Constrained Coding - PyCon 2016 - YouTube .

Number of symbols in base with an underscore count(x -> occursin("_", x), string.(names(Base))) Check if parentheses in a string are balanced check(s) = mapreduce(x->(x=='(')-(x==')'), (x,y)-> x<0 ? -1 : x+y, s)==0 Apply f to the elements of v and concatenate the result. mapconcat(f, v) = [z fo…

Here’s some alternatives for fun! But less fancy I suppose :frowning: count(@. occursin("_", string($names(Base)))) Even sum would work. mapconcat(f, v) = vcat([f(u) for u in v]...) pascal(n) = [binomial(i,j) for i in 0:n-1, j in 0:n-1] fib(n) = ([1 1; 1 0]^n)[1,1]

Sure. Note that a few of them are not very efficient (check, flatit).

Your use of the @. is nifty. And we can shorten mapconcat a bit mapconcat(f, v) = vcat(f.(v)...)

What’s the difference compared to just f.(v)?

Fun One Liners

General Usage

Tamas_Papp February 29, 2020, 6:40am 109

Some of these would be very useful in a tutorial about higher order functions that has been discussed. Would it be OK with you if they were used for that purpose?

Topic		Replies	Views
Seven Lines of Julia (examples sought) General Usage	184	30960	October 20, 2025
Sum operations between arrays Performance	21	5792	April 7, 2020
Julia-ism for two-dimensional map? New to Julia	22	3261	May 1, 2018
Efficient creation of power series matrix or array of arrays Performance question	23	5187	March 29, 2019
Usage of lazy vector instead of function Performance	22	1082	November 7, 2022

Fun One Liners

Related topics