Java Script. How to choose any few items of array

Question

I'm designing a quiz motivator, i.e. if a user inputs any number of correct answers he's gonna get rewarded with a "star" or smth. The array in a pseudo code below represents a range of correct answers to choose from:

var rightAnswers = ['a', 'b', 'c', 'd', 'e', 'f', 'g'];

if (rightAnswers.chooseAny(3)) {user gets a star}
else if (rightAnswers.chooseAny(6)) {user gets 2 stars}
else if (rightAnswers.chooseAny(9) {user gets 3 stars}

I haven't found anything that would work instead of my pseudo "chooseAny()", any ideas, please?

the name chooseAny is cryptic , explain further on your idea ? — Sujal Mandal
– Sujal Mandal, Commented Mar 7, 2017 at 3:35
Expected output is just a ranking - if any 3 answers of 15 in total are correct user gets 1 badge, if 6 are correct - 2 badges and so on. Each input is done through the inputField.value and matched with individual array of correct answers for each question — Andy
– Andy, Commented Mar 7, 2017 at 3:37
name chooseAny is not a part of the code it's just an idea of how i want it — Andy
– Andy, Commented Mar 7, 2017 at 3:38

gyre · Accepted Answer · 2017-03-07 03:46:29Z

1

You probably aren't looking for a chooseAny function; I think what you're really asking for is a way to count how many answers were correct given a set of answers and an answerKey.

The getTotalCorrect function below does that for you using a for-loop and identity comparison, and you can use getStars to determine how many stars should be awarded based on the score that is returned.

var answerKey = ['a', 'b', 'c', 'd', 'e', 'f', 'g']

function getTotalCorrect (answers, answerKey) {
  for (var correct = 0, i = 0; i < answerKey.length; i++) {
    if (answers[i] === answerKey[i]) correct++
  }
  return correct
}

function getStars (totalCorrect) {
   return (totalCorrect / 3) | 0
}

var totalCorrect = getTotalCorrect(['a', 'a', 'c', 'c', 'e', 'e', 'e'], answerKey)
console.log(totalCorrect) //=> 3

var stars = getStars(totalCorrect)
console.log(stars) //=> 1

answered Mar 7, 2017 at 3:46

gyre

16.8k4 gold badges41 silver badges47 bronze badges

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1 Comment

Andy Over a year ago

Thanks, that i guess i can make sense of!

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