如何计算Javascript中对象数组中不同值的出现次数？ [英] How to count number of occurrences of distinct values from an array of objects in Javascript?

问题描述

我有一系列对象如下：

var array =
    [
        {"name":"abc","age":20}
        {"name":"abc","age":20}
        {"name":"abc","age":20}
        {"name":"xyz","age":21}
        {"name":"xyz","age":21}
    ]

我想计算不同值的出现次数，例如：

I want to count the number of occurrences of distinct values like:

[3,2]

假设 abc 有3次出现， xyz 有2次出现。

Assuming abc has 3 occurrences and xyz has 2 occurrences.

我正在做在 reactjs 中。我能够使用 [abc，xyz] 来自javascript / 35092559中的对象数组的不同值＃35092559>此答案。

I am doing it in reactjs. I am able to get distinct values like [abc,xyz] using this answer.

_{ES6语法是首选。}

推荐答案

你需要知道伯爵属于哪个名字，所以我建议不要输出一个数组，它不会给你任何线索，但是一个由名称键入的对象，并带有相应计数值：

You'll need to know to which name a count belongs, so I propose not to output an array that gives you no clue about that, but an object keyed by names and with as value the corresponding count:

var result = array.reduce( (acc, o) => (acc[o.name] = (acc[o.name] || 0)+1, acc), {} );

var array =
    [
        {"name":"abc","age":20},
        {"name":"abc","age":20},
        {"name":"abc","age":20},
        {"name":"xyz","age":21},
        {"name":"xyz","age":21}
    ];
    
var result = array.reduce( (acc, o) => (acc[o.name] = (acc[o.name] || 0)+1, acc), {} );

console.log(result);

这篇关于如何计算Javascript中对象数组中不同值的出现次数？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！