I want to get an array random elemet from an intial array

Question

I have an initial array1 =[{id:"0",a:"4",b:"6"},{id:"1",a:"r",b:"8"},{id:"2",a:"8",b:"9"}] I want another array that contains random elements from the intial array

randomArray=[{id:"0",a:"4",b:"6"},{id:"2",a:"8",b:"9"}]

how can i do it?

your solution can be ```Math.random``` based. You have not described if the length of ```randomArray``` is less than the length of ```array1``` (otherwise you would have element repetition) — grodzi, Oct 24 '19 at 07:37
Pls, write more detail: how length of intial array, randomArray — Ryan Nghiem, Oct 24 '19 at 07:38

score 2 · Answer 1 · answered Oct 24 '19 at 07:38

2

You can use Array.prototype.filter and Math.random() like below;

const array1 =[{id:"0",a:"4",b:"6"},{id:"1",a:"r",b:"8"},{id:"2",a:"8",b:"9"}];
const filtered = array1.filter(() => Math.random() > 0.5);
console.log(filtered);

Note: The probability that every individual item is chosen is 50% in my solution.

answered Oct 24 '19 at 07:38

Diamond

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this has `50%` probability to return an empty array, use recursion to make sure it return at least one – Eslam Abu Hugair Oct 24 '19 at 07:41
1

@EslamAbuHugair Thanks but there is no requirement that the results should have at least one item. – Diamond Oct 24 '19 at 07:46
1

@EslamAbuHugair And the probability to return an empty array is `0.5 ^ array.length`. :) – Diamond Oct 24 '19 at 07:47

score 0 · Answer 2 · answered Oct 24 '19 at 08:09

const random = (array, length) => array.sort(() => 0.5 - Math.random()).slice(0, length);

const mock = [
  { id: "0", a: "4", b: "6" },
  { id: "1", a: "r", b: "8" },
  { id: "2", a: "8", b: "9" },
  { id: "3", a: "8", b: "9" }
];

console.log(random(mock, 2))
console.log(random(mock, 3))
console.log(random(mock, 4))

I want to get an array random elemet from an intial array

2 Answers2