为什么我的对象显示为“[object Object]”？ [英] Why are my objects showing up as "[object Object]"?

问题描述

我正在尝试按年龄对一系列记录进行冒泡排序，但我得到的只是：

I'm trying to bubble sort an array of records by age but all I get is:

[object Object]，[ object object]，[object Object]

[object Object], [object Object], [object Object]

如何让它显示记录的值？

How can I get it to display the values of the record?

students = [
    {name: "timothy", age: "9"},
    {name: "claire",  age: "12"},
    {name: "michael", age: "20"}
];

for (var i = 0; i < students.length; i++) {
    for (var j = i + 1; j < students.length; j++) {
        if (Number(students[i].age) > Number(students[j].age)) {
            tempValue = students[j].age;
            students[j].age = students[i].age;
            students[i].age = tempValue;
        }
    }
}

alert(students);

推荐答案

默认情况下，JavaScript中的所有对象都转为[object Object]将它们转换为字符串时（与 alert（）的情况一样）。

By default, all objects in JavaScript turn to "[object Object]" when they are converted to a string (as is the case with alert()).

您可以尝试：

• 使用console.log或调试器检查数组（而不是使用alert（））

• Use console.log or a debugger to inspect the array (instead of using alert())

console.log(students);
//Open your browser's developer tools to see the console.
//Try F12, ctrl+shift+J or ctrl+shift+I as shortcuts

使用 JSON.stringify 函数来序列化对象。

JSON.stringify({a:1});
//yields '{"a":1}'

给你对象自定义toString方法

Give your objects a custom toString method

var x = {
    a : 17,
    toString: function(){
        return 'I have a ' + this.a;
    }
};
alert(x); //gives "I have a 17"

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