Question

我正在尝试从下面的代码中解决两个问题。

var employees = [
    {
    firstName: "John",
    lastName :"Doe",
      qualification: {Diploma: 'IT Software' , Degree: 'Software Engineering'}
    }, 
    {
    firstName:"Anna",
    lastName:"Smith",
      qualification: {Diploma: 'Business Accountant' , Degree: 'Business Administration'}
    }
];

for(var i in employees)
  {
    console.log(employees[i]);

  }

以上代码的输出如下。

[object Object] {
  firstName: "John",
  lastName: "Doe",
  qualification: [object Object] {
    Degree: "Software Engineering",
    Diploma: "IT Software"
  }
}
[object Object] {
  firstName: "Anna",
  lastName: "Smith",
  qualification: [object Object] {
    Degree: "Business Administration",
    Diploma: "Business Accountant"
  }
}

我希望索引输出而不是[object object]它应该为相应的对象显示[index：1]和[index：2]。

我们将不胜感激。感谢

Answer 1

不要使用for-in（没有安全措施）来遍历数组（details and alternatives listed in this answer），这不是它的用途。

如果您想在数组中同时使用对象及其索引，那么最好的选择是forEach：

employees.forEach(function(employee, i) {
    console.log("[index: " + (i + 1) + "]");
    // And if you need the actual employee object,
    // it's `employee`
});

注意i + 1：JavaScript中的索引（以及一般的编程）通常以0开头，而不是1，因此为了获得所需的输出，我们在索引中添加一个。

或者，一个无聊的旧for循环：

for(var i = 0; i < employees.length; ++i)
{
    console.log("[index: " + (i + 1) + "]");
    // And if you need the actual employee object, as
    // with your code, it's `employees[i]`
}

Answer 2

当您在for bucle中循环数组时，您将获得带有变量 i 的索引

for(var i in employees)
    console.log("index:"+ i);

索引和访问JSON多维数组对象

2 个答案: