javascript - 迭代 javascript 数据对象并查找平均值的最佳方法

Question

我正在尝试迭代一个对象并显示对象内每个键的平均值。

假设我有:

data = {
  totals: {
    item1: {
      time: 15,
      speed: 20,
      amount: 12,
      units: 29
    },
    item2: {
      time: 3,
      speed: 75,
      amount: 14,
      units: 3
    },
    item3: {
      time: 19,
      speed: 4,
      amount: 44,
      units: 365
    }
  }
}

创建这些值的平均值的最佳方法是什么:

averages = {
  time: 12,
  speed: 33,
  amount: 40,
  units: 132
}

我知道将每个键值的总和除以总项目数，但我正在努力寻找一种好方法来迭代每个项目并将总数相加。这些项目将根据每个帐户的条目动态创建。

使用 for .. in 循环是最好的方法吗？如果是这样，我将如何使用它来实现这一目标？像下面这样的东西？

function findAverage() {
  const averages = {
    time: 0,
    speed: 0,
    amount: 0,
    units: 0
  }

  const totalItems = Object.keys(data.totals).length 

  for (item in data.totals) {
    averages.time += item.time;
    averages.speed += item.speed;
    averages.amount += item.amount;
    averages.units += item.units;
  }

  averages.time = averages.time / totalItems;
  averages.speed = averages.speed / totalItems;
  averages.amount = averages.amount / totalItems;
  averages.units = averages.units / totalItems;

  return averages;
}

有没有更好的方法来解决这个问题？我完全不做我在这里想做的事情吗？

Answer 1

您可以使用 Object.keys 和数组上的 reduce 方法来代替循环

function calculateAverage(totals) {
  const items = Object.keys(totals).reduce((result, item) => result.concat(totals[item]), [])
  const itemsCount = items.length;
   
  const metricsTotals = items.reduce((sums, item) => {
    sums.time += item.time
    sums.speed += item.speed
    sums.amount += item.amount
    sums.units += item.units
    return sums
  }, { time: 0, speed: 0, amount: 0, units: 0})

  return Object.keys(metricsTotals).reduce((average, metric) => {
    average[metric] = Math.floor(metricsTotals[metric] / itemsCount)
    return average
  }, {})
}

var data = {
  totals: {
    item1: {
      time: 15,
      speed: 20,
      amount: 12,
      units: 29
    },
    item2: {
      time: 3,
      speed: 75,
      amount: 14,
      units: 3
    },
    item3: {
      time: 19,
      speed: 4,
      amount: 44,
      units: 365
    }
  }
}


const averages= calculateAverage(data.totals)
console.log(averages)