如何在javascript中对对象数组中的值求和

Question

我有一个对象数组，如下所示：

[
    {
        Daypart: "G_POSTPEAK",
        day_of_week: "Monday",
        uplift: 1
    },
    {
        Daypart: "A_BREAKFAST",
        day_of_week: "Thursday",
        uplift: 1
    },
    {
        Daypart: "C_DAYTIME",
        day_of_week: "Sunday",
        uplift: 2
    },
    {
        Daypart: "G_POSTPEAK",
        day_of_week: "Monday",
        uplift: 2
    },
]

我只展示了数组中的一个对象样本，我正在处理更多的对象。它们都具有指定的属性，daypart属性可以是8个值中的一个，而星期的值可以是7(一周中的几天)中的一个。

我想返回具有相同daypart和day_of_week值的所有对象的提升值的总和。

因此，上面的代码应该返回如下内容：

{
    G_POSTPEAK_Monday: {
        Daypart: "G_POSTPEAK",
        day_of_week: "Monday",
        uplift: 3
    },
    A_BREAKFAST_Thursday: {
        Daypart: "A_BREAKFAST",
        day_of_week: "Thursday",
        uplift: 1
    },

    C_DAYTIME_Sunday: {
        Daypart: "C_DAYTIME",
        day_of_week: "Sunday",
        uplift: 2
    }
}

感谢任何帮助

Answer 1

可以使用以下函数。我用过ES6。该函数以inputs作为输入对象。

​

const sumIt = (inputs) => {
  const result = {};
  inputs.forEach((input) => {
    const key = `${input.Daypart}_${input.day_of_week}`;
    if (key in result) {
      result[key].uplift = result[key].uplift + input.uplift;
    } else {
      result[key] = { ...input };
    }
  });
  return result;
};

​

Answer 2

您可以使用ES6 reduce函数在一行中执行求和，而不是使用foreach。

​

let array = [
    {
        Daypart: "G_POSTPEAK",
        day_of_week: "Monday",
        uplift: 1
    },
    {
        Daypart: "A_BREAKFAST",
        day_of_week: "Thursday",
        uplift: 1
    },
    {
        Daypart: "C_DAYTIME",
        day_of_week: "Sunday",
        uplift: 2
    },
    {
        Daypart: "G_POSTPEAK",
        day_of_week: "Monday",
        uplift: 2
    },
];

const totalUplift = array.reduce((acc, array) => acc + array.uplift, 0);

console.log(totalUplift);

​

Answer 3

可以使用array#reduce根据对象累加器中的Daypart和day_of_week对数据进行分组。

​

let data = [ { Daypart: "G_POSTPEAK", day_of_week: "Monday", uplift: 1 }, { Daypart: "A_BREAKFAST", day_of_week: "Thursday", uplift: 1 }, { Daypart: "C_DAYTIME", day_of_week: "Sunday", uplift: 2 }, { Daypart: "G_POSTPEAK", day_of_week: "Monday", uplift: 2 }],
    result = data.reduce((r,o) => {
      let key = `${o.Daypart}_${o.day_of_week}`;
      r[key] = r[key] || {...o, uplift: 0};
      r[key].uplift += o.uplift;
      return r;
    },{});
console.log(result);

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

​