Create a 1D array of all 2D combinations [11,12,13,...32,33] from a 1D array [1,2,3]

Question

From a 1D array [1,2,3], create a 1D array of all 2D combinations 11,12,13,...32,33. I can do it, it's just a bit ugly. Is there a neater way to write it?

const intArr = [1,2,3];

const data = intArr.map(v1 => 
    intArr.map(v2 => v1 + ',' + v2)
).flat();

d3.select('ul')
    .selectAll('li')
    .data(data)
    .enter()
    .append('li')
    .text(d => d)

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
<ul></ul>

Its opinion based question. I would use nested loop and `document.createElement` — Jan Pfeifer, Jan 09 '23 at 14:38
I use d3 because the page is already using d3 for other things. — Ksthawma, Jan 09 '23 at 14:44

score 0 · Answer 1 · answered Jan 09 '23 at 14:45

0

arr.map(n => arr.map(m => '' + n + m)).flat()

is a completely valid way of creating a cartesian product in Javascript. You can also do

arr.flatMap(n => arr.map(m => '' + n + m))

answered Jan 09 '23 at 14:45

JollyJoker

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Create a 1D array of all 2D combinations [11,12,13,...32,33] from a 1D array [1,2,3]

1 Answers1