Create a set of four unique numbers in an array with four digits each

Question

Create a set of four unique numbers in an array with four digits each

let gameScope = {}

function generateUniqueNum() {
    gameScope.uniqueNumbers = [];
    for (let j = 0; j < 4; j++) {
        let number = Math.floor((Math.random() * 9)+1);
        if (!gameScope.uniqueNumbers.includes(number)) {
            gameScope.uniqueNumbers.push(number);
        } else {
            j--;
        }
    }
    return gameScope.uniqueNumbers;
}

Hey there! I'm new to learning JavaScript and I have an assignment to create a 4 digit array with unique numbers ranging from 1 to 9 (for a game similar to Bulls and Cows). I'm having trouble figuring out how to check this array for repeated numbers. Any help would be greatly appreciated. Thanks!

javascript arrays

Answer 1

Answer №1

If you prefer, you have the option to utilize a source array that includes all numbers from 0 to 9, and then select and delete one of them each time:

function generateNumber(){
    var targetArray = [], // target array
        sourceArray = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0], // source array
        sourceLength = sourceArray.length,
        index, randomIndex;

    for (index=0; index<4; index++) {
        randomIndex = Math.floor(Math.random() * (sourceLength - index)); // choose a random index
        // remove the selected number from the source and add it to the target array
        targetArray.push(sourceArray.splice(randomIndex, 1)[0]);
    }

    // return the resulting array
    return targetArray;
}

To learn more about the .splice method, visit MDN.

Answer 2

If you prefer, you have the option to utilize a source array that includes all numbers from 0 to 9, and then select and delete one of them each time:

function generateNumber(){
    var targetArray = [], // target array
        sourceArray = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0], // source array
        sourceLength = sourceArray.length,
        index, randomIndex;

    for (index=0; index<4; index++) {
        randomIndex = Math.floor(Math.random() * (sourceLength - index)); // choose a random index
        // remove the selected number from the source and add it to the target array
        targetArray.push(sourceArray.splice(randomIndex, 1)[0]);
    }

    // return the resulting array
    return targetArray;
}

To learn more about the .splice method, visit MDN.

Answer 3

Answer №2

To efficiently obtain a set of random digits, the ideal approach involves utilizing an array containing all possible digits and then retrieving them individually:

let allDigits = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
    outcome = [];
for (let j = 0; j < 5; j++) {
    outcome[j] = allDigits.splice(Math.floor((Math.random() * allDigits.length) + 1, 1);
}
return outcome;

Answer 4

To efficiently obtain a set of random digits, the ideal approach involves utilizing an array containing all possible digits and then retrieving them individually:

let allDigits = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
    outcome = [];
for (let j = 0; j < 5; j++) {
    outcome[j] = allDigits.splice(Math.floor((Math.random() * allDigits.length) + 1, 1);
}
return outcome;

Answer 5

Answer №3

If you're approaching this task from a beginner's perspective, the first step is to outline the necessary steps needed to accomplish it.

Pseudocode:

1. Generate a random number.
2. Add the random number to an array.
3. Loop until the array length reaches 4:
4.    Generate another random number.
5.    Check if the number already exists in the array.
6.    If the number is not already in the array, add it.

Creating the code is made simple by following these steps. Start by generating a random number and pushing it into an array. Then, use a while loop until array.length === 4. Generate additional numbers within this loop and utilize a for loop to verify if the number is already present in the array.

for (var i = 0; i < array.length; i++) {
   //Check for existence here
}

Answer 6

If you're approaching this task from a beginner's perspective, the first step is to outline the necessary steps needed to accomplish it.

Pseudocode:

1. Generate a random number.
2. Add the random number to an array.
3. Loop until the array length reaches 4:
4.    Generate another random number.
5.    Check if the number already exists in the array.
6.    If the number is not already in the array, add it.

Creating the code is made simple by following these steps. Start by generating a random number and pushing it into an array. Then, use a while loop until array.length === 4. Generate additional numbers within this loop and utilize a for loop to verify if the number is already present in the array.

for (var i = 0; i < array.length; i++) {
   //Check for existence here
}

Answer 7

Answer №4

let gameData = {}


function createNumbers() {
    gameData.randomNums = [];
    while (gameData.randomNums.length < 4) {
        let num = Math.floor((Math.random() * 9) + 1);
        if (gameData.randomNums.indexOf(num) < 0) {
            gameData.randomNums.push(num);
        }
    }
    return gameData.randomNums;  
}

Answer 8

let gameData = {}


function createNumbers() {
    gameData.randomNums = [];
    while (gameData.randomNums.length < 4) {
        let num = Math.floor((Math.random() * 9) + 1);
        if (gameData.randomNums.indexOf(num) < 0) {
            gameData.randomNums.push(num);
        }
    }
    return gameData.randomNums;  
}

Answer 9

Answer №5

This particular method could be precisely what you're seeking:

Start by selecting a random position within the range of [0,10-i)
Next, append the number at position #index to the resulting array
Lastly, copy the number at position #i into position #index

function generateNumber()
{
    var numbers = [0,1,2,3,4,5,6,7,8,9];
    var resultArray = [];
    for (var i=0; i<4; i++)
    {
        var position = Math.floor(Math.random() * (10 - i));
        resultArray += numbers[position];
        numbers[position] = numbers[10 - i];
    }
    return resultArray;
}

Answer 10

This particular method could be precisely what you're seeking:

Start by selecting a random position within the range of [0,10-i)
Next, append the number at position #index to the resulting array
Lastly, copy the number at position #i into position #index

function generateNumber()
{
    var numbers = [0,1,2,3,4,5,6,7,8,9];
    var resultArray = [];
    for (var i=0; i<4; i++)
    {
        var position = Math.floor(Math.random() * (10 - i));
        resultArray += numbers[position];
        numbers[position] = numbers[10 - i];
    }
    return resultArray;
}

Create a set of four unique numbers in an array with four digits each

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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