javascript 使用 underscore.js 从对象数组中获取最小值和最大值
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Get the min and max from array of objects with underscore.js
提问by sarsnake
Let's say I have the following structure
假设我有以下结构
var myArrofObjects = [
{prop1:"10", prop2:"20", prop3: "somevalue1"},
{prop1:"11", prop2:"26", prop3: "somevalue2"},
{prop1:"67", prop2:"78", prop3: "somevalue3"} ];
I need to find the min and max based on prop2, so here my numbers would be 20 and 78.
我需要根据 prop2 找到最小值和最大值，所以这里我的数字是 20 和 78。
How can I write code in Underscore to do that?
如何在 Underscore 中编写代码来做到这一点？
回答by
You don't really need underscore for something like this.
对于这样的事情，你真的不需要下划线。
Math.max(...arrayOfObjects.map(elt => elt.prop2));
If you're not an ES6 kind of guy, then
如果你不是 ES6 那种人，那么
Math.max.apply(0, arrayOfObjects.map(function(elt) { return elt.prop2; }));
Use the same approach for minimum.
对最小值使用相同的方法。
If you're intent on finding max and min at the same time, then
如果你想同时找到最大值和最小值，那么
arrayOfObjects .
map(function(elt) { return elt.prop2; }) .
reduce(function(result, elt) {
if (elt > result.max) result.max = elt;
if (elt < result.min) result.min = elt;
return result;
}, { max: -Infinity, min: +Infinity });
回答by Meir
use _.max and _.property:
使用 _.max 和 _.property：
var max value = _.max(myArrofObjects, _.property('prop2'));
回答by Nadeeshaan
You can use the _.maxBy to find max value as follows.
您可以使用 _.maxBy 来查找最大值，如下所示。
var maxValObject = _.maxBy(myArrofObjects, function(o) { return o.prop2; });
or with the iteratee shorthand as follows
或使用 iteratee 简写如下
var maxValObject = _.maxBy(myArrofObjects, 'prop2');
similarly the _.minBy as well;
_.minBy 也类似；
回答by ykay says Reinstate Monica
Use _.max as follows:
使用 _.max 如下：
var max_object = _.max(myArrofObjects, function(object){return object.prop2})
Using a function as the second input will allow you to access nested values in the object as well.
使用函数作为第二个输入还允许您访问对象中的嵌套值。
回答by svarog
Underscore
下划线
use _.sortBy(..) to sort your object by a property
使用 _.sortBy(..) 按属性对对象进行排序
var sorted = _.sortBy(myArrofObjects, function(item){
return item.prop2;
});
you will then get a sorted array by your prop1 property, sorted[0]is the min, and sorted[n]is the max
然后你会得到一个按你的 prop1 属性排序的数组，sorted[0]是最小值，sorted[n]是最大值
Plain JS
纯JS
myArrofObjects.sort(function(a, b) {
return a.prop2 - b.prop2;
})
