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I need to create an array (observations) which contains arrays of eight numbers (named observation). These numbers should be in range between 0 and 9.

let observations = [];
let observation = [];
let min = 0;
let max = 9;
for (let i = 0; i < 20000; i++) {
    for (let j = 0; j < 8; j++) {
        observation[j] = Math.floor(Math.random() * (max - min + 1)) + min;
    }
    observations.push(observation);
}

Problem: The numbers are pseudo random and I get the same result 20 000 times.

Is there a possibility to fix this issue in JavaScript?

You're reusing the same observation array each time, but simply overwriting it in the inner loop. So all the references to it contain the results from the last iteration.

You need to create a new observation array each time through the outer loop.

let observations = [];
let min = 0;
let max = 9;
for (let i = 0; i < 20000; i++) {
    let observation = [];
    for (let j = 0; j < 8; j++) {
        observation.push(Math.floor(Math.random() * (max - min + 1)) + min);
    }
    observations.push(observation);
}

Fill an array with random numbers, Generating an array of random integers in JavaScript is surprisingly easy. Here are 3 ways to do it. Math.random function returns us a random number in the range of 0 - 1; Math.random() * colors.length, we get a random number between 0 - 1, let's say 0.5 and normalize it, multiplying it by the length of the array (so we don't get the index larger that our array's length); Math.floor(Math.random() * colors.length), gives us a random integer (array index) by rounding-down our normalized value to the nearest integer.

You could move the empty array inside of the first level, because you keep the same object reference.

let observations = [];
let min = 0;
let max = 9;
for (let i = 0; i < 20000; i++) {
    let observation = [];
    for (let j = 0; j < 8; j++) {
        observation[j] = Math.floor(Math.random() * (max - min + 1)) + min;
    }
    observations.push(observation);
}

Using Math.random() in JavaScript - Joe Cardillo, How do you create an array of random numbers in Java? In order to generate random array of integers in Java, we use the nextInt() method of the java.util.Random class. This returns the next random integer value from this random number generator sequence. Declaration − The java.util.Random.nextInt() method is declared as follows − public int nextInt()

Math.seed = function(s) {
    return function() {
        s = Math.sin(s) * 10000; return s - Math.floor(s);
    };
};

let observations = [];
let observation = [];
let min = 0;
let max = 9;
for (let i = 0; i < 20000; i++) {
        var d = new Date();
        var n = d.getMilliseconds();
    for (let j = 0; j < 8; j++) {
        observation[j] = Math.floor(Math.seed(i+j+n)() * (max - min + 1)) + min;
    }
    observations.push(observation);
    observation = [];
}

JSON.stringify(observations);

How do you generate a random value from an array? Output: Random Number between 1 and 5: 1.0573617826058959. Method 2: Using Math.floor () function: The Math.floor () function in JavaScript is used to round off the number passed as parameter to its nearest integer in Downward direction of rounding i.e towards the lesser value.

A functional solution:

const observations = Array.from({length: 20000}, () => 
  Array.from({length: 10}, () => (Math.random() * 10 | 0)))

random() to generate a number between 0–1 (inclusive of 0, but not 1) randomly. Then multiply the random number with the length of the array  See the Pen JavaScript - Get a random item from an array - array-ex- 35 by w3resource (@w3resource) on CodePen. Improve this sample solution and post your code through Disqus Previous: Write a JavaScript function to get nth largest element from an unsorted array.

javascript-array-of-random-values.js. function randomDataSet(dataSetSize, minValue, maxValue) {. return new Array(dataSetSize).fill(0).map(function(n) {. The random () method returns a random number from 0 (inclusive) up to but not including 1 (exclusive). Browser Support. Technical Details. A Number, representing a number from 0 up to but not including 1. JavaScript Version: Return a random number between 1 and 10: Math.floor( (Math.random() * 10) + 1); Try it Yourself »

random() and Math.floor() method to get the random values. Push the values one by one in the array (But this approach may generate repeated values). As you can see from the examples above, it might be a good idea to create a proper random function to use for all random integer purposes. This JavaScript function always returns a random number between min (included) and max (excluded): Example. function getRndInteger (min, max) {. return Math.floor(Math.random() * (max - min) ) + min;

The random(a, b) method is used to generates a number between(a to b, b exclusive). Taking the floor value to range the numbers from (1 to arrayLength). In this topic, we are going to learn about the Random Number Generator in JavaScript. Random Number in JavaScript. Almost, every programming language has its built-in function to the same. JavaScript also has a function to get a random number. There is a various way we can get the random number in JavaScript, let’s see with some example.