使用数组中数组的索引调用数组元素 JavaScript

Question

我想在 JS 中制作一个调查应用程序，我的主要代码如下：

for(var questionNumber in questionsAndAnswers.allQuestions){
      for(var i in questionsAndAnswers.allQuestions[questionNumber]){
        console.log(questionsAndAnswers.allQuestions[questionNumber].question);
        console.log(questionsAndAnswers[questionNumber+1]);
    } 
}

配置中的这段代码：

const questionsAndAnswers = {
    "allQuestions": [
        { "question": "Write your first question here",
        },
        { "question": "Write your second question here",
        },
        { "question": "Write your third question here",
      }
     ],
    "answerOne": [
        "1.This is the first answer",
        "1.This is the second answer",
        "1.This is the third answer"
        ],
    "answerTwo": [
        "2.This is the first answer",
        "2.This is the second answer",
        "2.This is the third answer"
      ],
     "answerThree": [
        "3.This is the first answer",
        "3.This is the second answer",
        "3.This is the third answer"
      ]
}

然后是这样的：

Write your first question here
undefined
Write your second question here
undefined
Write your third question here
undefined

我想这样做：当第一个问题被问到时，只有第一个答案出现，但是当我调用 console.log(questionsAndAnswers[questionNumber+1]);Undefined 时出现。我尝试了很多选项，但主要问题是将问题与答案分开，并在 config 更改时动态添加问题 + 答案，而不更改 main。如果你能帮助我，我将非常感激。

谢谢！

Answer 1

questionNumber是一个表示索引的整数。因此，对于第一项 questionNumber === 0，您正试图从 questionsAndAnswers[0 + 1] === questionsAndAnswers[1] 获得答案。由于您的对象上没有属性 "1"，因此它是未定义的。

如果你想使用与此类似的数据结构，我建议如下：

for(var questionNumber in questionsAndAnswers.allQuestions){
  console.log(questionsAndAnswers.allQuestions[questionNumber].question);
  for(var i in questionsAndAnswers.allAnswers[questionNumber]){
    console.log(questionsAndAnswers[questionNumber][i]);
  } 
}

const questionsAndAnswers = {
  "allQuestions": [
    { "question": "Write your first question here" },
    { "question": "Write your second question here" },
    { "question": "Write your third question here" }
  ],
  "allAnswers": [
    [
      "1.This is the first answer",
      "1.This is the second answer",
      "1.This is the third answer"
    ],
    [
      "2.This is the first answer",
      "2.This is the second answer",
      "2.This is the third answer"
    ],
    [
      "3.This is the first answer",
      "3.This is the second answer",
      "3.This is the third answer"
    ]
  ]
}

但是，我鼓励您探索组织数据结构的不同方式，因为这种方式看起来有点奇怪。也许尝试为问题和答案创建单独的对象，或者在问题下嵌套答案。

Answer 2

我认为您应该重新考虑您的数据模型。您的 questionsAndAnswers 是一个对象，这意味着您不是通过整数而是通过键（"answerOne"、"answerTwo"、...）访问问题。因此 questionsAndAnswers[questionNumber+1] 不起作用。它必须类似于 questionsAndAnswers["answerOne"].

但是我建议您将答案保存在您的问题对象中。

{
    "question": "Write your first question here",
    "answers": [...]
}

Answer 3

我用了Tushar说的：

I suggest to store the question & answers in same object. { question: "abc", answers: ["abc", "def", ghi"], correct: 0}.

谢谢

使用数组中数组的索引调用数组元素 JavaScript

Calling array element with index from an array inside the array JavaScript

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