CODEWITHSUNDEEP
javascriptarrays
Richlewis
Richlewis

Reputation: 15384

Select 2 Random values within my array

Im learning some javascript and have hit a stumbling block.. I would like to select 2 random values from my array and save them into a variable (which will be another array i guess) called Deal, i can get one random value but not 2.. My code is as follows

var deckOfCards = []; //declaring an empty array to put Cards into later

function Card(name, value, altValue) { //function that defines a card object ( key part is "this")
this.cardName = name;
this.cardValue = value;
this.cardAltValue = altValue || false;
}

var suits = ['Hearts', 'Diamonds', 'Spades', 'Clubs'];
var values = ['Ace', 'Two', 'Three', 'Four', 'Five', 'Six', 'Seven', 'Eight', 'Nine', 'Ten', 'Jack', 'Queen', 'King'];

for(var i in suits) //loops through each of the suits
{
 for(var j in values) { // loops through each of the cards for the suit

if(values[j] != 'Ace') {//j is the index within the array,
    var cardValue = parseInt(j, 10) + 1; 
    if(cardValue > 10) cardValue = 10;
    deckOfCards.push(new Card(values[j] +' of ' +suits[i], cardValue));//adding   a new card object to deckOfCards
} else {
    deckOfCards.push(new Card(values[j] +' of ' +suits[i], 1, 11));// adding alternate value to deckOfCards
}

   }

  }


var Deal = deckOfCards[Math.floor(Math.random()*deckOfCards.length)];;
console.log(Deal);

Could anyone give me a pointer on this please

Thanks

Upvotes: 2

Views: 578

Answers (5)

ChuckCottrill
ChuckCottrill

Reputation: 4444

You might consider shuffling the entire deck of cards (randomize all 52 cards), and then dealing becomes simply pulling the top card from the deck.

  • Declare an array of all cards, deckOfCards[], define to list of cards,
  • Declare a shuffle of all cards, ShuffleDeck[]
  • Randomize picking all cards from deckOfCards[], copied into ShuffleDeck[]
  • The deal becomes pulling the top card from ShuffleDeck

An observation that might help is that the shuffled deck only needs to have an index into the defined deckOfCards, so it is just a randomized set of values 0..51 (or 1..52 as you prefer).

//define your cards
deckOfCards[] = ... //left up to you

//define Dealt[], to make checking whether already shuffled, dealt
card = 0 //or 1, however you prefer
while (card<52) {
    Dealt[card] =0; card++;
}


//Shuffle
card = 0 //or 1, however you prefer
while (card<52) {
    //try to pick a card not yet shuffled
    pick = Math.floor(Math.random()*deckOfCards.length);
    while (Dealt[pick]) { //used, pick again
        pick = Math.floor(Math.random()*deckOfCards.length);
    }
    Dealt[card] =1; //used
    ShuffleDeck[card] =pick; card++;
}

//now dealing becomes simply
top=0
//define a function to deal a card
var deal = function() {
    if( !(top<52) ) {
        return -1; //or, handle error here
    }
    result = top;
    top++;
    return result; //work with indices
    //or
    //return deckOfCards[ShuffleDeck[result]];
}
carddealt = deal();

//deal two cards to a Hand,
Hand[player].push( deal() );
Hand[player].push( deal() );

//suppose you want to deal four hands, five cards each
round = 0;
while (round < 5 ) {
    hand = 0;
    while (hand < 4 ) {
        Hand[hand].push( deal() );
    }
}

Alternately, you could drop each card dealt form the shuffled[] as you deal it.

Upvotes: 2

MackieeE
MackieeE

Reputation: 11872

var cardsHeld = {};
for( var x = 0; x < 2; x++ ) {
    var newCard = deckOfCards[Math.floor(Math.random()*deckOfCards.length)];
    //If Not found within current CardsHeld Obj, Append.
    if ( !cardsHeld.hasOwnProperty( newCard.cardName )) {
        cardsHeld[newCard.cardName] = newCard;
    }
}

console.log( cardsHeld );
/**
 * Prints:
 *    Object
 *       Five of Spades: Card
 *       Two of Hearts: Card
 */

Fiddle: http://jsfiddle.net/MguBJ/1/

Upvotes: 1

applepicke
applepicke

Reputation: 96

function randomCard(deck, numToExtract) {
    var extracted = [];
    for (var i = 0; i < numToExtract; i++){
        extracted.push(deck.splice(Math.floor(Math.random()*deckOfCards.length, 1));
    }
    return extracted;
}

The return value will be an array of cards extracted from the deck, and the deck array will have those cards taken out. You will need to keep track of where the cards are and make sure none 'disappear'.

Upvotes: 2

Tony Dinh
Tony Dinh

Reputation: 6726

Try this:

var Deal = deckOfCards[Math.floor(Math.random()*deckOfCards.length)];
var Deal2 = deckOfCards[Math.floor(Math.random()*deckOfCards.length)];
while (Deal2.equals(Deal)) { // if you want Deal and Deal2 have to different
    Deal2 = deckOfCards[Math.floor(Math.random()*deckOfCards.length)];
}

You need to implement the equals function as well.

function Card(name, value, altValue) {
    this.cardName = name;
    this.cardValue = value;
    this.cardAltValue = altValue || false;

    equals = function(otherObject) {
        return (otherObject.cardName == this.cardName && otherObject.cardValue == this.cardValue && otherObject.cardAltValue == this.cardAltValue)
    }
}

Upvotes: 1

Joe Enos
Joe Enos

Reputation: 40413

You've got a couple choices. You can either just call the same random function against the full deck a second time, then ensure that the second value is different from the first (with a while loop), or you can actually remove the card from the deck the first time, using something like splice, then you can keep calling that until the deck is empty.

The splice option is probably the better one.

Upvotes: 1

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