# Generate array with random numbers in JavaScript

In this tutorial, you will see how to generate an array with random numbers in JavaScript. For this purpose, I am going to use `math.random` function which generates a random value. There are some processes explained below to generate an array with random numbers.

### Using fill() and map() method:

The `fill()` method fills the array with specified values and modifies the original array. The original array can be overwritten by the `fill()` method. This method returns the modified array.

The `map()` method creates a new array for each array element by calling a function.

```const array = Array(6)
.fill()
.map(() => 20 * Math.random());

console.log(array);```

In the above program, I have created an array and set the length of the array is 6. You can set the length as you wish.

After that, I used `fill()` method to fill and get a modified array with specified values.

Then `map()` method is used to call  `Math.random()` to generate a random number for each element of the array. It will generate random numbers between 0 to 20.

Output:

`[12.048939937650399, 4.046154574188345, 5.935852248559588, 1.814147075940209, 3.8275124919563135, 7.5750526847358834]`

As you can see in the output I got an array with some random float numbers. The length of the array is 6 and all the value is between 0 to 20.

• We can generate integers instead of float numbers by using `Math.floor()` method.
```const array = Array(6)
.fill()
.map(() => Math.floor(20 * Math.random()));
console.log(array);```

Output:

`[5, 7, 8, 17, 4, 13]`

You can see in the above output I got an array with 6 random integers which are between 0 to 20.

### Array.from() method:

The `Array.form()` method allows us to create a new shallow copied array instance from an array-like or iterable object. This method returns a new array instance.

```const array = Array.from({ length: 6 }, () => Math.random() * 20);
console.log(array);```

Here, I have used `Array.from()` method to create and fill the array with random numbers.

`And length: 6` to get 6 random numbers in the array.

Output:

`[17.584355709602807, 4.592638665589184, 9.169604019402087, 18.911980963502725, 5.550500753145147, 13.721315247919275]`

• We can generate integers instead of float numbers by using `Math.floor()` method.
```const array = Array.from({ length: 6 }, () => Math.floor(Math.random() * 20));
console.log(array);```

Output:

`[6, 5, 9, 7, 18, 11]`

### Notes:

To generate integers you can also use `Math.round()` method instead of `math.floor()` method.