Here I try to understand how to create array of arrays: I created one array but how to create an array of arrays, in which every array has 10 random numbers?
var arrRand = [];
while(arrRand.length < 10){
var random = Math.floor(Math.random() * 10) + 1;
if(arrRand.indexOf(random) === -1) arrRand.push(random);
}
console.log(arrRand);
A functional approach with every number being random.
let x = Array(4).fill().map(
() => Array(10).fill().map(
() => Math.floor(Math.random() * 10)
)
);
console.log(x);
You can use Math.random and a nested for loop. Here is an example:
let arr = [];
for(let i = 0; i < 4; i++){
let current = [];
for(let j = 0; j < 10; j++)
current.push(Math.floor(Math.random() * 10));
arr.push(current);
}
console.log(arr)In order to keep clean and dry code, you can use map function in ES6 syntax.
const x = [...Array(6)].map(
() => [...Array(10)].map(
() => Math.floor(Math.random() * 10) + 1
)
)
console.log(x)
[...Array(10)] instead of Array(10).fill() to make them mappable, but that's not better actually: It only saves 2 characters and it is less efficient, because the interpreter would initialize two arrays, iterating through the inner to generate the outer. I would stick to my answer.[...Array(6)] is useless redundant version of Array(6)
[...Array(6)] as it is an array in the map function. Not a big deal with the code performance but it brings a clean code and intuitive sense.let a = Array(4).fill(Array(10).fill(null))
Then fill it with Math.random() in loop
