sort（），sort（function（a，b）{return a-b;}）之间的区别;和排序（函数（a，b）{...}） [英] Difference between sort(), sort(function(a,b){return a-b;}); and sort(function(a,b){...})

问题描述

我正在尝试理解sort（）的工作方式以及我应该如何使用它。

I am trying to understand how exactly sort() works and how I am supposed to use it.

我做了一些研究（谷歌）并经历了类似的关于stackoverflow的问题，但仍有一些事情不是100％清楚的。

I did some research (google) and went through the similar questions here on stackoverflow, but there are still a few things not 100% clear to me.

所以到目前为止我的理解如下：

So my understanding so far is the following:

有：

没有参数的sort（）：只对 String的简单数组进行排序值按字母顺序以及升序顺序

例如

// sort alphabetically and ascending:
var myArr=["Bob", "Bully", "Amy"]
myArr.sort() // Array now becomes ["Amy", "Bob", "Bully"]

使用函数作为参数的sort（）：根据数组属性对数组中的对象进行排序;但是，这些项目会比较为数字

sort() with a function as a parameter: sorts objects in arrays according to their properties; the items are, however, compared as numbers

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

使用函数作为参数的sort（）：根据数组属性对数组中的对象进行排序;这些项目可以是数字或字符串

sort() with a function as a parameter: sorts objects in arrays according to their properties; the items can be numbers or Strings

myArr.sort(function(a, b) {
    if (a.sortnumber < b.sortnumber) return -1;
    else if (a.sortnumber > b.sortnumber) return 1;
    return 0;
});

我尝试使用所有这3个sort（）函数对以下数组进行排序。

I tried sorting the following array with all these 3 sort() functions.

var myArr = [{
  "sortnumber": 9,
  "name": "Bob"
},
{
  "sortnumber": 5,
  "name": "Alice"
},
{
  "sortnumber": 4,
  "name": "John"
},
{
  "sortnumber": 3,
  "name": "James"
},
{
  "sortnumber": 7,
  "name": "Peter"
},
{
  "sortnumber": 6,
  "name": "Doug"
},
{
  "sortnumber": 2,
  "name": "Stacey"
}];

//myArr.sort(); // doesn't do anything since it doesn't know on what property to sort

/*
myArr.sort(function(a, b) {
    return (a.sortnumber - b.sortnumber); // sorts array
    return (a.name - b.name); // doesn't sort array
});
*/

/*
// sorts array even when I use name as property to sort on
myArr.sort(function(a, b) {
    if (a.sortnumber < b.sortnumber) return -1;
    else if (a.sortnumber > b.sortnumber) return 1;
    return 0;
});
*/


console.log(myArr);

这里也是一个小提琴。

所以，我的问题是：

1. 我的理解是否正确？


2. 我有什么遗漏吗？


3. 如果第三种情况一直有效，我可以吗？总是坚持它或者是
   其他两种情况在某些方面更有效率或对
   第三种情况有任何好处？

如果有人能详细说明，我会非常感激以上。谢谢。

I would really appreciate it if anyone could elaborate on the above. Thank you.

推荐答案

好的，经过一些额外的研究后，请浏览 MDN文档，以及 arraysort 和 arraysort2 链接，我发现非常有帮助，我创建了一个可能对其他人有用的幻灯片，所以我在这里发布它。谢谢大家的答案！

Ok, so after some additional research, going through the MDN documentation, and the arraysort and arraysort2 links, which I found very helpful, I created a slide that could probably be of use to someone else, so I am posting it here. Thank you all for your answers!

< img src =https://i.stack.imgur.com/81miP.pngalt =在此处输入图像说明>

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