获取对象键的最高数值N值 [英] Get highest numeric N values of Object keys

问题描述

var foo = {a:1, b:2, c:3, d:4, e:5, f:6, g:7}

通缉结果:(获得前3个键价值）

Wanted result: (get top 3 keys by value)

{e:5, f:6, g:7}

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说明：

对于给定的密钥/ value基本对象，你如何获得3个顶部值，但不仅仅是值而是键？钥匙可以是任何东西。假设值是整数。

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Explanation:

For a given key/value basic object, how would you get the 3 top values, but not just the values but also the keys? keys could be anything. lets say values are integers.

应该记住性能。

推荐答案

您可以将属性提取到数组中，然后对数组进行排序：

You can extract the properties into an array, then sort the array:

var foo = {a:1, b:2, c:3, d:4, e:5, f:6, g:7}
var props = Object.keys(foo).map(function(key) {
  return { key: key, value: this[key] };
}, foo);
props.sort(function(p1, p2) { return p2.value - p1.value; });
var topThree = props.slice(0, 3);

如果您希望将结果作为对象，只需将其缩减为一个

If you want the result as an object, just reduce it back to one

var topThreeObj = props.slice(0, 3).reduce(function(obj, prop) {
  obj[prop.key] = prop.value;
  return obj;
}, {});

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