Javascript冒泡与对象的数组

beginner here!

Recently stumbled upon a problem. Basically, the program needs to sort an array of objects by one of their fields without actually using the sort function. I've tried this code using bubble sort algorithm, but it doesn't seem to be working:

最近偶然发现了一个问题。基本上,程序需要通过其中一个字段对对象数组进行排序,而不实际使用sort函数。我已经使用冒泡排序算法尝试了这个代码,但它似乎没有起作用:

var arrayOfPeople = [
    {name: "Rick", age: 30, place: 2},
    {name: "Alan", age: 25, place: 1},
    {name: "Joe", age: 40, place: 4},
    {name: "Dave", age: 35, place: 3}
];


function bubbleSort(a,par)
{
    var swapped;

    do {
        swapped = false;

        for (var i = 0; i < a.length - 1; i++) {
            if (a[i].par > a[i + 1].par) {
                var temp = a[i];

                a[i] = a[i + 1];
                a[i + 1] = temp;

                swapped = true;
            }
        }
    } while (swapped);
}


bubbleSort(arrayOfPeople,'age');

for (i = 0; i < arrayOfPeople.length; i++) {
    console.log(arrayOfPeople[i]);
}

My guess is that I'm doing something wrong syntax-wise. Will appreciate any feedback.

我的猜测是我在语法方面做错了。将不胜感激任何反馈。

2 个解决方案

#1

The only problem was that you were not using the "par" argument correctly. The obj.prop syntax will always try to look for property named "prop" so to have it dynamic you need to use square brackets e.g. obj["prop"] which can get variable instead of "prop".

唯一的问题是你没有正确使用“par”参数。 obj.prop语法将始终尝试查找名为“prop”的属性,因此要使其具有动态性,您需要使用方括号,例如obj [“prop”]可以变量而不是“prop”。

You didn't get any errors as a[i].par and a[i+1].par both returned undefined which can be compared to itself. (hence a[i].par > a[i+1].par always returns false)

你没有得到任何错误,因为[i] .par和[i + 1] .par都返回undefined,可以与自身进行比较。 (因此a [i] .par> a [i + 1] .par总是返回false)

Here is revised code that works:

以下是修改后的代码:

function bubbleSort(a, par)
{
    var swapped;
    do {
        swapped = false;
        for (var i = 0; i < a.length - 1; i++) {
            if (a[i][par] > a[i + 1][par]) {
                var temp = a[i];
                a[i] = a[i + 1];
                a[i + 1] = temp;
                swapped = true;
            }
        }
    } while (swapped);
}


bubbleSort(arrayOfPeople, 'age');

for (i = 0; i < arrayOfPeople.length; i++) {
   console.log(arrayOfPeople[i]);
}

Live test case.

现场测试案例。

Worth to mention in this context, that the function changing the actual object (array in this case) is not a trivial thing. To learn more what is passed by value and what is passed by reference take a look in this excellent question: Is JavaScript a pass-by-reference or pass-by-value language?

值得一提的是,在这种情况下,改变实际对象的函数(在这种情况下是数组)并不是一件小事。要了解更多通过值传递的内容以及通过引用传递的内容,请查看以下优秀问题:JavaScript是通过引用传递还是按值传递语言?

#2

Use the built in array sort function:

使用内置数组排序功能:

arrayOfPeople.sort(function(a,b) {return a.age-b.age;});

#1