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# JavaScript - generate array with 10 random numbers

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In this article, we would like to show you how to generate array with 10 random numbers in JavaScript.

Quick solution:

// ONLINE-RUNNER:browser;

const array = Array(10) // array size is 10
.fill()
.map(() => 50 * Math.random()); // numbers from 0-50 (exclusive)

console.log(array);

Note:

Use Math.floor() to get integers instead of float numbers. You can find practical examples in the sections below.

## Using Array.fill() with map() method

In this example we take the following steps:

1. Create an array with size 10,
2. Use fill() method to fill the array with specified values,
3. use map() method to call Math.random() to generate a random value for each element in the array (from 0-50 exclusive).

Practical example:

// ONLINE-RUNNER:browser;

const array = Array(10) // array size is 10
.fill()
.map(() => 50 * Math.random()); // numbers from 0-50 (exclusive)

console.log(array);

If you want to receive integers instead of float numbers use Math.floor() method:

Practical example:

// ONLINE-RUNNER:browser;

const array = Array(10) // array size is 10
.fill()
.map(() => Math.floor(50 * Math.random())); // numbers from 0-50 (exclusive)

console.log(array);

## Using Array.from() method (ES6+)

In this example, we use Array.from() method to create an array with size 10 and fill it with random numbers.

Practical example:

// ONLINE-RUNNER:browser;

// The solution for ES6+
const array = Array.from({ length: 10 }, () => Math.random() * 50);
console.log(array);

If you want to receive integers instead of float numbers use Math.floor() method:

Practical example:

// ONLINE-RUNNER:browser;

// The solution for ES6+
const array = Array.from({ length: 10 }, () => Math.floor(Math.random() * 50));
console.log(array);

## Using crypto object

In this example, you can find solution that lets to randomize arrays using embedded crypto object.

Source code:

// ONLINE-RUNNER:browser;

const randomArray = (length, constructor = Uint32Array) => {
const array = new constructor(length);
return crypto.getRandomValues(array);
};

// Usage example:

console.log(randomArray(5, Uint8Array));      // also: Int8Array
console.log(randomArray(5, Uint16Array));     // also: Int16Array
console.log(randomArray(5, Uint32Array));     // also: Int32Array
console.log(randomArray(5, BigUint64Array));  // also: BigInt64Array

Note: the solution was intruduced in major web browsers in 2011-2014.

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## JavaScript - Arrays (popular problems)

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