如何在javascript中对这个对象数组进行分组或合并？

Question

我有一个像下面这样的对象数组.

{name: "Mc Donald", quantity: 4, maleCount: 1, femaleCount: 0}
{name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0}
{name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0}
{name: "Mc Donald", quantity: 4, maleCount: 0, femaleCount: 1}
{name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1}
{name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0}
{name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1}
{name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1}

我想将它们分组并将其中的所有值相加.例如,决赛将是这样的:

{name: "Mc Donald", quantity: 8, maleCount: 1, femaleCount: 1}
{name: "KFC", quantity: 54, maleCount: 3, femaleCount: 3}

我怎样才能在JavaScript中实现这一目标？

我试图在网上找到一些解决方案,但它不是我想要的.例如这个解决方案

Answer 1

你可以使用array reduce:

var arr = [
    {name: "Mc Donald", quantity: 4, maleCount: 1, femaleCount: 0},
    {name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0},
    {name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0},
    {name: "Mc Donald", quantity: 4, maleCount: 0, femaleCount: 1},
    {name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1},
    {name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0},
    {name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1},
    {name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1}
];

var finalArr = arr.reduce((m, o) => {
    var found = m.find(p => p.name === o.name);
    if (found) {
        found.quantity += o.quantity;
        found.maleCount += o.maleCount;
        found.femaleCount += o.femaleCount;
    } else {
        m.push(o);
    }
    return m;
}, []);

console.log(finalArr);

Answer 2

您可以使用forEach()循环并添加到新数组.您可以将空对象作为thisArg参数传递,您可以this在回调函数中使用该参数,并且在第二个forEach上下文中this仍然会因为箭头函数而与第一个回调函数中的相同.

var data = [{"name":"Mc Donald","quantity":4,"maleCount":1,"femaleCount":0},{"name":"KFC","quantity":9,"maleCount":1,"femaleCount":0},{"name":"KFC","quantity":9,"maleCount":1,"femaleCount":0},{"name":"Mc Donald","quantity":4,"maleCount":0,"femaleCount":1},{"name":"KFC","quantity":9,"maleCount":0,"femaleCount":1},{"name":"KFC","quantity":9,"maleCount":1,"femaleCount":0},{"name":"KFC","quantity":9,"maleCount":0,"femaleCount":1},{"name":"KFC","quantity":9,"maleCount":0,"femaleCount":1}]
var result = [], keys = ['quantity', 'maleCount', 'femaleCount']

data.forEach(function(e) {
  if(!this[e.name]) result.push(this[e.name] = e);
  else keys.forEach(k => this[e.name][k] += e[k])
}, {})

console.log(result)

Answer 3

您可以使用哈希表进行分组,并使用数组作为具有变量值的键.

var array = [{ name: "Mc Donald", quantity: 4, maleCount: 1, femaleCount: 0 }, { name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0 }, { name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0 }, { name: "Mc Donald", quantity: 4, maleCount: 0, femaleCount: 1 }, { name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1 }, { name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0 }, { name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1 }, { name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1 }],
    groups = Object.create(null),
    result = array.reduce(function (r, o) {
        var values = ['quantity', 'maleCount', 'femaleCount'];
        if (!groups[o.name]) {
            groups[o.name] = { name: o.name };
            r.push(groups[o.name]);
            values.forEach(function (k) { groups[o.name][k] = 0; });
        }
        values.forEach(function (k) { groups[o.name][k] += o[k]; });
        return r;
    }, []);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

使用linq.js

var array = [{ name: "Mc Donald", quantity: 4, maleCount: 1, femaleCount: 0 }, { name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0 }, { name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0 }, { name: "Mc Donald", quantity: 4, maleCount: 0, femaleCount: 1 }, { name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1 }, { name: "KFC", quantity: 9, maleCount: 1, femaleCount: 0 }, { name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1 }, { name: "KFC", quantity: 9, maleCount: 0, femaleCount: 1 }],
    result = Enumerable.From(array)
        .GroupBy(
            "$.name",
            null,
            "{ name: $.Key, quantity: $$.Sum('$.quantity'), maleCount: $$.Sum('$.maleCount'), femaleCount: $$.Sum('$.femaleCount') }"
        )
        .ToArray();

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

<script src="https://cdnjs.cloudflare.com/ajax/libs/linq.js/2.2.0.2/linq.js"></script>