Javascript测试-使用Array.prototype以随机顺序显示选项

Javascript quiz - display choices in a random order using Array.prototype

本文关键字：随机顺序显示选项 prototype 测试使用 Array Javascript 更新时间：2023-09-26

我想随机化选择的顺序。我添加了一个本应打乱选择顺序的脚本，但它没能做到。当我调试测试时，什么都没有显示。

这是我添加的代码：

function shuffle(array) {
  var currentIndex = array.length, temporaryValue, randomIndex;
  // While there remain elements to shuffle...
  while (0 !== currentIndex) {
    // Pick a remaining element...
    randomIndex = Math.floor(Math.random() * currentIndex);
    currentIndex -= 1;
    // And swap it with the current element.
    temporaryValue = array[currentIndex];
    array[currentIndex] = array[randomIndex];
    array[randomIndex] = temporaryValue;
  }
  return array;
}

Javascript测验：

 var quiz = [{
          "question": "What is the full form of IP?",
          "choices": ["Internet Provider", "Internet Port", "Internet Protocol" , "Other"],
          "correct": "Other"
        }, {
          "question": "Who is the founder of Microsoft?",
          "choices": ["Bill Gates", "Steve Jobs", "Steve Wozniak" , "Martin Shaba"],
          "correct": "Bill Gates"
        }, {
          "question": "What was your first dream?",
          "choices": ["8 bits", "64 bits", "1024 bits"],
          "correct": "8 bits"
        }, {
          "question": "The C programming language was developed by?",
          "choices": ["Brendan Eich", "Dennis Ritchie", "Guido van Rossum"],
          "correct": "Dennis Ritchie"
        }, {
          "question": "What does CC mean in emails?",
          "choices": ["Carbon Copy", "Creative Commons", "other"],
          "correct": "Carbon Copy"
        }];

向Array.prototype:添加scramble函数

if (!("scramble" in Array.prototype)) {
  Object.defineProperty(Array.prototype, "scramble", {
    enumerable: false,
    value: function() {
      var o, i, ln = this.length;
      while (ln--) {
        i = Math.random() * (ln + 1) | 0;
        o = this[ln];
        this[ln] = this[i];
        this[i] = o;
      }
      return this;
    }
  });
}
var quiz = [{
  "question": "What is the full form of IP?",
  "choices": ["Internet Provider", "Internet Port", "Internet Protocol", "Other"],
  "correct": "Other"
}];
quiz.forEach(q => q.choices.scramble());
console.log(quiz[0].choices);

最初我建议：

quiz.forEach(q => q.choices.sort(() => Math.random() - .5));

DanDavis指出，这种特殊的方法并没有达到合理的分布。

如果您希望"其他"在洗牌后保留为最后一个选择，您可以使用以下代码来完成：

var quiz = [{
  "question": "What is the full form of IP?",
  "choices": ["Internet Provider", "Internet Port", "Internet Protocol", "Other"],
  "correct": "Other"
}, {
  "question": "Who is the founder of Microsoft?",
  "choices": ["Bill Gates", "Steve Jobs", "Steve Wozniak", "Martin Shaba"],
  "correct": "Bill Gates"
}, {
  "question": "What was your first dream?",
  "choices": ["8 bits", "64 bits", "1024 bits"],
  "correct": "8 bits"
}, {
  "question": "The C programming language was developed by?",
  "choices": ["Brendan Eich", "Dennis Ritchie", "Guido van Rossum"],
  "correct": "Dennis Ritchie"
}, {
  "question": "What does CC mean in emails?",
  "choices": ["Carbon Copy", "Creative Commons", "Other"],
  "correct": "Carbon Copy"
}];
function shuffle(array) {
    var temporaryValue, randomIndex;
    var currentIndex = array.length;
    // While there remain elements to shuffle...
    while (currentIndex > 1) {
        // Pick a remaining element...
        randomIndex = Math.floor(Math.random() * currentIndex);
        currentIndex -= 1;
        // And swap it with the current element.
        temporaryValue = array[currentIndex];
        array[currentIndex] = array[randomIndex];
        array[randomIndex] = temporaryValue;
    }
    return array;
}
quiz.forEach(function(question) {
    var otherIndex;
    var choices = question.choices;
    var lastIndex = choices.length - 1;
    shuffle(choices);
    otherIndex = choices.indexOf('Other');
    if (otherIndex >= 0) {
        choices[otherIndex] = choices[lastIndex];
        choices[lastIndex] = 'Other';
    }
    console.log(choices);
});