无法通过括号变量表示法访问对象属性

Question

我试图通过方括号表示法访问对象属性之一，但是我无法弄清为什么它不起作用。 一如既往，非常感谢您的帮助！

js：

    var dude = [
      {
        question1: "What is dude's favourite food?",
        choices1: ["Pizza", "Pasta", "Chips", "Ice cream"],
        answer1: 1

      },
      {
        question2: "What was dude's first ever job?",
        choices2: ["Staples", "Vodafone", "Costa", "Post office"],
        answer2: 0
      },

    ]

var counter = 1;

var currentQues = "question"+counter;

console.log(dude[currentQues]);

控制台返回“未定义”。 这是因为它无法通过本质上包含另一个变量（计数器）的变量（currentQues）访问属性吗？

与往常一样，我们非常感谢您的帮助。 我只是想进步的初学者。

Answer 1

dude是指对象数组 。 您正在尝试在dude上访问question1 ，但是您需要在dude[0]上访问它：

console.log(dude[0][currentQues]);
// -------------^^^

现场示例：

 var dude = [ { question1: "What is dude's favourite food?", choices1: ["Pizza", "Pasta", "Chips", "Ice cream"], answer1: 1 }, { question2: "What was dude's first ever job?", choices2: ["Staples", "Vodafone", "Costa", "Post office"], answer2: 0 }, ] var counter = 1; var currentQues = "question"+counter; console.log(dude[0][currentQues]); 

---

我强烈建议您重新考虑该数据结构。 所有对象的对象属性名称都应该相同，只是它们在数组中的位置可以区分它们：

 var dude = [{ question: "What is dude's favourite food?", choices: ["Pizza", "Pasta", "Chips", "Ice cream"], answer: 1 }, { question: "What was dude's first ever job?", choices: ["Staples", "Vodafone", "Costa", "Post office"], answer: 0 }, ] dude.forEach(function(entry, index) { var num = index + 1; console.log("Question #" + num + ": " + entry.question); }); 

Answer 2

您还需要获取数组的索引。

 var dude = [{ question1: "What is dude's favourite food?", choices1: ["Pizza", "Pasta", "Chips", "Ice cream"], answer1: 1 }, { question2: "What was dude's first ever job?", choices2: ["Staples", "Vodafone", "Costa", "Post office"], answer2: 0 }], counter = 1; currentQues = "question" + counter; console.log(dude[counter - 1][currentQues]); // ^^^^^^^^^^^