Trying to push a pair of array values into a another array randomly without duplicates javascript

Question

I'm trying to make an memory card game but this part is hard to figure out. I have an array with a deck of cards and I'm trying to select a specific amount cards in pairs randomly from the deck of cards and push them into the gameBoard array but I intitally keep getting duplicate of the pairs. Basically I trying to shuffle cards. I tried using a conditional statement but i dont know if this right way to go about this but it still doesnt work.

javascript

const deckOfCards = [
  'card1',
  'card2',
  'card3',
  'card4',
  'card8',
  'card9',
  'card10',
  'card11',
  'card12',
  'card13',
  'card14',
]


let shuffle = deckOfCards[Math.floor(Math.random() * deckOfCards.length)];
let pair = [shuffle, shuffle]
let len = mode

for (let i = pair; i < deckOfCards.length; i++) {
  if (gameBoard.indexOf(deckOfCards[i]) === -1) {
    gameBoard.push(deckOfCards[pair])
  }
}
console.log(gameBoard)
});
let gameBoard = []

So pair will contain a list with 2 same random elements from deckOfCards, right? So what's the purpose of the for loop started with pair? Since pair is an array with 2 elements. Can you clarify what's your expected result? — Trung Hieu Nguyen
– Trung Hieu Nguyen, Commented Aug 15, 2021 at 13:15
I would suggest you use _.shuffle from underscore library. — zx01
– zx01, Commented Aug 15, 2021 at 13:16
it's a memory card game so i wanted the pair to run through the loop and output random different pairs without a duplicate — ericstlouis
– ericstlouis, Commented Aug 15, 2021 at 13:23

C. Z. Chen · Accepted Answer · 2021-08-15 13:37:18Z

2

just a thought: you can move the selected element to the back of the array and then randomly select stuff from a slice of the prior, unchanged array... just like array.slice(0, {a_number_here}.

something like this I guess (I cannot get your code working so this is not tested yet):

let shuffle = deckOfCards[Math.floor(Math.random() * deckOfCards.length - 5)]
name = deckOfCards.splice(shuffle, 1)
deckOfCards.push(name)

by the way if you can use libraries, just go for underscore.js and it would become very simple. just like this:

b = _.shuffle(deckOfCards).slice(0,5);
console.log(b)

you can also take a look at these repositories too (I haven't yet had the chance to take a look at them though but they kinda have a lot of stars so):

edited Aug 15, 2021 at 13:37

answered Aug 15, 2021 at 13:21

C. Z. Chen

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2 Comments

ericstlouis Over a year ago

yeah. I know but this is for school so only vanilla javascript... but I will try your orginal idea

C. Z. Chen Over a year ago

ah that is lame... I mean why don't them allow libraries if you are going to use them in future anyway...

Islam Baidaq · Accepted Answer · 2021-08-15 13:15:55Z

0

you can copy existing one to new one ex : const cloneSheepsES6 = [...sheeps]; then you can apply your condition without any duplications

answered Aug 15, 2021 at 13:15

Islam Baidaq

264 bronze badges

1 Comment

ericstlouis Over a year ago

I will look into this

zx01 · Accepted Answer · 2021-08-15 13:46:02Z

0

This should give you an array of unique pair of cards.

const deckOfCards = [
  "card1",
  "card2",
  "card3",
  "card4",
  "card8",
  "card9",
  "card10",
  "card11",
  "card12",
  "card13",
  "card14",
];

const randomArray = [];
let noOfPairs = 6; // No. of pairs required

while (noOfPairs) {
  let randomNumber = Math.floor(Math.random() * deckOfCards.length);
  if (randomArray.includes(randomNumber)) {
    continue;
  }
  randomArray.push(randomNumber);
  noOfPairs--;
}

randomArray.sort(() => 0.5 - Math.random());

const gameBoard = randomArray.map((item) => [
  deckOfCards[item],
  deckOfCards[item],
]);
console.log(gameBoard);

answered Aug 15, 2021 at 13:46

zx01

5816 silver badges17 bronze badges

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