Array practice question

Question

/* 7. Use a for loop to loop through the deck and list each card in the order the appear in the newly shuffled array. Use the log() method to print out a message like this, once for each card: "7 of ♥.︎" */ for (let i = 0; i<myDeck.length; i++) { console.log(myDeck[i][0]+ ' of ' + myDeck[i][1]);
}

Hi, First I dont understand the inner loop and outer loop, is it means when you run the first item in the outer loop, then it will load the rest of inner loop. When you load the second item in the outer loop, then it will load the rest of inner loop and so on. Is it true? Or inner loop first and outer loop second? Finally, there is shuffle algorithem i cant understand, can anyone explain to me detailed, thank you so much!

Answer 1 · 2019-07-22T10:02:33Z

July 22, 2019 10:02am

"Q1. I don't understand the inner loop and outer loop, is it means when you run the first item in the outer loop, then it will load the rest of inner loop. When you load the second item in the outer loop, then it will load the rest of inner loop and so on. Is it true? Or inner loop first and outer loop second?"

See comments in the code. It will run the code in the order it will find it. In this case the 'outer loop' first, and then runs all of the code in it once. In this case that is another loop. That loop will start to run and will create a card. And does that for all the cards that are in the ranks.

Once they all are done, the outer loop will start another iteration, namely the second iteration. And so fort.

Final result with comments:

function createDeck() {
  var suites = ['♠︎','♣︎','♥︎','♦︎'];
  var ranks = ['Ace','King','Queen','Jack','10','9','8','7','6','5','4', '3','2'];
  var deck = [];

  // Q1: It runs four times, each time for a suite
  for (let indexSuites = 0; indexSuites < suites.length; indexSuites++) {

     // Q1: each time, run the number of ranks (ranks.length) before returning to next iteration
     for(let indexRanks = 0; indexRanks < ranks.length; indexRanks++) {
       let card = [];
       card.push(ranks[indexRanks]);
       card.push(suites[indexSuites]);
       // the deck is updated here each time a card is created
       deck.push(card);
     }
  }

  // The deck should only be returned once, therefore it's outside of the for loops
  // Also, the deck should be shuffled:
  return shuffle(deck);
}

const myDeck = createDeck();

for(let i = 0; i < myDeck.length; i++) {
  const card = myDeck[i];
  console.log(`${card[0]} of ${card[1]} `);
}

"Q2 Finally, there is shuffle algorithem i cant understand, can anyone explain to me detailed."

There is a source provided in the teachers notes for the shuffle algorithm: https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle

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MIHA W.LEE

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Array practice question

1 Answer

Remi Vledder

Remi Vledder

MIHA W.LEE

MIHA W.LEE