javascript Javascript按布尔属性对对象数组进行排序

Javascript sort array of objects by a boolean property

提问by PCoelho

See edit at end for actual problem.

有关实际问题，请参阅最后的编辑。

Ok, I have this scenario:

好的，我有这个场景：

a = [false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false]

Then if I do this:

那么如果我这样做：

a.sort(function(a,b){return !a && b});

It gives me this:

它给了我这个：

[false, false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, false, true, false, false, false, false, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false]

It's sorta doing a sort... but not quite... :(

有点像在做某种事情......但不完全...... :(

How do I sort this array?

我如何对这个数组进行排序？

EDIT:

编辑：

If you are wondering why I did not use just a.sort() is because my actual array is of objects, not a plain array like the one I posted. The real one has elements that look like [{xx:true},{xx:false},...]

如果你想知道为什么我不只使用 a.sort() 是因为我的实际数组是对象，而不是像我发布的那样的普通数组。真正的元素看起来像 [{xx:true},{xx:false},...]

回答by c.P.u1

a = [false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false];
    
    
    a.sort(function(x, y) {
        // true values first
        return (x === y)? 0 : x? -1 : 1;
        // false values first
        // return (x === y)? 0 : x? 1 : -1;
    });
    
    console.log(a);

You must return 0 when a and b both have the same value, -1 if a is true and 1 otherwise.

当 a 和 b 具有相同的值时，您必须返回 0，如果 a 为真，则返回 -1，否则返回 1。

回答by dandavis

a simpler way:

一个更简单的方法：

a = [{xx:true},{xx:false},{xx:true},{xx:false},{xx:true},{xx:false},{xx:true},{xx:false},{xx:true},{xx:false},{xx:true},{xx:false},{xx:true},{xx:false},{xx:true},{xx:false},{xx:true},{xx:false}];

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

console.log(a);

you can call a.reverse() after the sort() if you want it sorted the other way..

如果你希望它以另一种方式排序，你可以在 sort() 之后调用 a.reverse()。

EDIT: edited to reflect updated question of sorting an array of objects instead of an array of booleans.

编辑：编辑以反映对对象数组而不是布尔数组进行排序的更新问题。

回答by sroes

To prevent implicit type conversion (which languages like TypeScript don't like), you can use Number()to explicitly convert the boolean to a number:

为了防止隐式类型转换（TypeScript 等语言不喜欢），您可以使用Number()将布尔值显式转换为数字：

a = [false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false];
a.sort(function(x, y) {
   return Number(x) - Number(y);
});
console.log(a);

Or using arrow functions:

或者使用箭头函数：

a = [false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false];
a.sort((x, y) => Number(x) - Number(y));
console.log(a);

回答by Сергей Мисник

Simple solution:

简单的解决方案：

[true, false, true, false].sort( (a,b) => b - a)

回答by Kristjan Liiva

An array does not have any equal positions, so why not leave away the equals check, and always return either -1 or 1. This approach works well with TS.

数组没有任何相等的位置，所以为什么不放弃相等检查，并始终返回 -1 或 1。这种方法适用于 TS。

a.sort(x => x ? -1 : 1)

Note: I am a bit concerned how this affects internals of the sort function, but it seems to do the trick.

注意：我有点担心这会如何影响 sort 函数的内部结构，但它似乎可以解决问题。

If you want to reverse sort

如果你想反向排序

a.sort(x => !x ? -1 : 1)

回答by dreamdeveloper

PFB the solution worked for me in Typescript Angular 2 as well,

PFB 该解决方案在 Typescript Angular 2 中也对我有用，

  let a = [{aa:"1",xx:true},{aa:"10",xx:false},{aa:"2",xx:true},{aa:"11",xx:false},{aa:"3",xx:true},{aa:"12",xx:false},{aa:"4",xx:true},{aa:"13",xx:false},{aa:"5",xx:true},{aa:"14",xx:false},{aa:"6",xx:true},{aa:"15",xx:false},{aa:"7",xx:true},{aa:"16",xx:false},{aa:"8",xx:true},{aa:"17",xx:false},{aa:"9",xx:true},{aa:"18",xx:false}];

    //a.sort(function(a,b){return a.xx-b.xx});
    a.sort(function (x, y) {
        // true values first
        return (x.xx === y.xx) ? 0 : x ? -1 : 1;
        // false values first
        // return (x === y)? 0 : x? 1 : -1;
    });
    return JSON.stringify(a);

回答by MattCochrane

A pretty simple solution for the comparison function is to check if a < b, this gives 0 or 1 when converted to a number. We then want to map 0 to -1 and 1 to 1. To do that you can just multiply by 2 then subtract 1.

比较函数的一个非常简单的解决方案是检查 if a < b，这在转换为数字时给出 0 或 1。然后我们想将 0 映射到 -1，将 1 映射到 1。为此，您只需乘以 2 再减去 1。

data.sort(function (a, b) {
  return (a < b) * 2 - 1
}

or just

要不就

data.sort((a, b) => (a < b) * 2 - 1)

Problem sorted!

问题已解决！

If any of your values are nullthey are treated as false (null*2 === 0) and any value that is undefinedwill become NaN(undefined*2 === NaN) which should make it last in either sort direction.

如果您的任何值是null它们，它们将被视为 false ( null*2 === 0) 并且任何值都undefined将变为NaN( undefined*2 === NaN) 这应该使其在任一排序方向持续。

回答by chriscrossweb

I got typescript errors on the return (x.xx === y.xx) ? 0 : x ? -1 : 1;

我的打字稿错误 return (x.xx === y.xx) ? 0 : x ? -1 : 1;

This is my solution when you want to sort on a boolean property

当您想对布尔属性进行排序时，这是我的解决方案

this.mediaList.sort( (a: MediaAutosubscriptionModel, b: MediaAutosubscriptionModel) => {
    let status1: number = a.status === StatusEnum.ACTIVE ? 1 : 0;
    let status2: number = b.status === StatusEnum.ACTIVE ? 1 : 0;
    let comparison: number = 0;
    let direction: number = this.sortDirection === SortDirectionsEnum.ASC ? -1 : 1;
    if (status1 > status2) {
        comparison = direction;
    } else if (status1 < status2) {
        comparison = -1 * direction;
    }
        return comparison;
    });

回答by toddmo

I wanted to see if I could do it without using the ? :operator, just for fun.

我想看看我是否可以在不使用? :运算符的情况下做到这一点，只是为了好玩。

Note

笔记

This works on all sortable data types (strings, numbers), not just raw booleans. I'm not sure if this is faster than ? :and it's more convoluted. I just get sick of conditionals so it's just personal preference.

这适用于所有可排序的数据类型（字符串、数字），而不仅仅是原始布尔值。我不确定这是否比? :它更快并且更复杂。我只是厌倦了条件，所以这只是个人喜好。

  var b = [false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false]
  .sort((a,b) => Number(a > b) * 2 - 1);

I can turn that into a utility function and give it a meaningful name:

我可以把它变成一个实用函数并给它一个有意义的名字：

  var sortOrder = {
    asc: (a,b) => Number(a > b) * 2 - 1,
    desc: (a,b) => Number(a < b) * 2 - 1
  }

so then I can:

那么我可以：

  var b = [false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false]
  .sort(sortOrder.asc);