如何找到對象數組的所有屬性的最小值、最大值和平均值

Question

我有一個包含不同值的對象數組，我想找到該數組中屬性的最小值、最大值和平均值

例如，如果我有一個數組

 const array = [{ "a": "-0.06", "b": "0.25", "c": "-0.96", "d": "-0.14" }, { "a": "-0.37", "b": "0.01", "c": "-0.77", "d": "-0.09" }, { "a": "0.01", "b": "0.88", "c": "-0.53", "d": "-0.28" }, { "a": "0.53", "b": "-0.62", "c": "0.02", "d": "0.74" }, { "a": "0.79", "b": "-0.39", "c": "0.70", "d": "0.18" }, { "a": "0.74", "b": "-0.14", "c": "0.22", "d": "-0.58" } ]

所以輸出將如下所示

 const out = [{ property: a, minValue: -0.37, maxValue: .79, avg: 0.2733333333333334 }, { property: b, minValue: -.62, maxValue: .88, avg: -0.0016666666666666496 }, { property: c, minValue: -.96, maxValue: .07, avg: -0.21999999999999997 }, { property: d, minValue: -.58, maxValue: .74, avg: -0.028333333333333332 }]

因此，為了獲得輸出，我們迭代數組並找到 a、b、c 和 d 的最小值、最大值和平均值，並將其存儲在一個新數組中

Answer 1

這是一個兩步的方法。 首先，我使用reduce對屬性上的數組進行分組。 然后我在分組對象上執行了一個map來獲得最小值、最大值和平均值

 const array = [{ "a": "-0.06", "b": "0.25", "c": "-0.96", "d": "-0.14" }, { "a": "-0.37", "b": "0.01", "c": "-0.77", "d": "-0.09" },{ "a": "0.01", "b": "0.88", "c": "-0.53", "d": "-0.28" }, { "a": "0.53", "b": "-0.62", "c": "0.02", "d": "0.74" }, { "a": "0.79", "b": "-0.39", "c": "0.70", "d": "0.18" }, { "a": "0.74", "b": "-0.14", "c": "0.22", "d": "-0.58" }] const grouped = array.reduce((acc,curr) => { Object.entries(curr).forEach(([property,v])=>{ acc[property] = acc[property] || [] acc[property].push(+v) //+ for convert to a number before pushing }) return acc },{}) const out = Object.entries(grouped).map(([property,v]) => { return { property, minValue: Math.min(...v), // min of an array. v is the array of numbers maxValue: Math.max(...v), //max of an array avg: v.reduce((a, b) => a + b) / v.length //average of an array } }) console.log(out)

Answer 2

您使用 Array.reduce 並從一個類似於結果但具有極值的對象開始，因此對於 min 有最大值。 或者，根據您的規范，它對於任何空輸入數組都是未定義的。

Answer 3

這是一種方法，首先我們制作一個看起來像這樣的地圖

{ a : ['-0.06', '-0.06', '-0.37', '0.01', '0.53', '0.79', '0.74'] 
 b: ['0.25', '0.25', '0.01', '0.88', '-0.62', '-0.39', '-0.14'],
 ...
}

然后我們對地圖中的每個值運行一個循環以找到最大值、最小值和平均值。

 const array = [{ "a": "-0.06", "b": "0.25", "c": "-0.96", "d": "-0.14" }, { "a": "-0.37", "b": "0.01", "c": "-0.77", "d": "-0.09" },{ "a": "0.01", "b": "0.88", "c": "-0.53", "d": "-0.28" }, { "a": "0.53", "b": "-0.62", "c": "0.02", "d": "0.74" }, { "a": "0.79", "b": "-0.39", "c": "0.70", "d": "0.18" }, { "a": "0.74", "b": "-0.14", "c": "0.22", "d": "-0.58" }] const getStats = (data) => { const valueMap = {}; data.forEach((item) => { Object.entries(item).forEach(([key, value]) => { if (!valueMap[key]) { valueMap[key] = [value]; } valueMap[key].push(value); }); }); return Object.entries(valueMap).map(([key, value]) => ({ property: key, ...getMinMaxAndAvg(value) })); }; const getMinMaxAndAvg = (arr) => { let minValue = Number.MAX_VALUE; let maxValue = Number.MIN_VALUE; let total = 0; arr.forEach((val) => { if (val > maxValue) { maxValue = val; } if (val < minValue) { minValue = val; } total += +(val); }); return { minValue, maxValue, avg: total / arr.length }; }; console.log(getStats(array));

Answer 4

使用以下函數：`

const createNewObj = (previous, current) => ({
  minValue: Math.min(previous, current,
  maxValue: Math.max(previous, current,
  total: previous + current,
  length: previous.length + 1,
  avg: (previous + current) / (previous.length + 1)
})

const default = {
  minValue: 0,
  maxValue: 0,
  total: 0,
  length: 0,
  avg: 0
}

array.reduce((previous, current) => {
a: createNewObj(previous[a], current[a]), 
b: createNewObj(previous[b], current[b]), 
c: createNewObj(previous[c], current[c]), 
d: createNewObj(previous[d], current[d])
}
, {
a: default,
b: default, 
c: default, 
d: default
})

`

Answer 5

我遵循了一個兩步過程-

1. 對每個屬性的值進行分組（為此使用reduce ）
2. 循環遍歷所有屬性並計算所需的結果。

 const array = [{ "a": "-0.06", "b": "0.25", "c": "-0.96", "d": "-0.14" }, { "a": "-0.37", "b": "0.01", "c": "-0.77", "d": "-0.09" },{ "a": "0.01", "b": "0.88", "c": "-0.53", "d": "-0.28" }, { "a": "0.53", "b": "-0.62", "c": "0.02", "d": "0.74" }, { "a": "0.79", "b": "-0.39", "c": "0.70", "d": "0.18" }, { "a": "0.74", "b": "-0.14", "c": "0.22", "d": "-0.58" }] const out = []; const newObj = array.reduce((prevValue, currValue) => { Object.keys(currValue).forEach((el) => { if (prevValue[el]) { prevValue[el].push(Number(currValue[el])); } else { prevValue[el] = [Number(currValue[el])]; } }); return prevValue; }, {}); Object.keys(newObj).forEach((el) => { out.push({ property: el, minValue: Math.min(...newObj[el]), maxValue: Math.max(...newObj[el]), avg: newObj[el].reduce((a, b) => a + b, 0) / newObj[el].length }); }); console.log(out);

Answer 6

const array = [{
    "a": "-0.06",
    "b": "0.25",
    "c": "-0.96",
    "d": "-0.14"
  },
  {
    "a": "-0.37",
    "b": "0.01",
    "c": "-0.77",
    "d": "-0.09"
  },
  {
    "a": "0.01",
    "b": "0.88",
    "c": "-0.53",
    "d": "-0.28"
  },
  {
    "a": "0.53",
    "b": "-0.62",
    "c": "0.02",
    "d": "0.74"
  },
  {
    "a": "0.79",
    "b": "-0.39",
    "c": "0.70",
    "d": "0.18"
  },
  {
    "a": "0.74",
    "b": "-0.14",
    "c": "0.22",
    "d": "-0.58"
  }
]

var out = [

]

Object.keys(array[0]).map(v=>{//this is so it runs for all 4 properties 
    let temp = {
  property:v
  }
  //sort array to get min and max
  let ary = [...array].sort((a,b)=>{
    return a-b
  })
  /* console.log(ary) */
  let avg = 0;
  ary.map(i=>{
    avg = avg+Number(i[v]);
  })
  temp.avg = avg/array.length
  temp.minValue = ary.pop()[v]
  temp.maxValue = ary.shift()[v]
  out.push(temp)
})
console.log(out)

見菲德爾

Answer 7

以下是您可以使用的代碼片段

 const array = [{ "a": "-0.06", "b": "0.25", "c": "-0.96", "d": "-0.14" }, { "a": "-0.37", "b": "0.01", "c": "-0.77", "d": "-0.09" }, { "a": "0.01", "b": "0.88", "c": "-0.53", "d": "-0.28" }, { "a": "0.53", "b": "-0.62", "c": "0.02", "d": "0.74" }, { "a": "0.79", "b": "-0.39", "c": "0.70", "d": "0.18" }, { "a": "0.74", "b": "-0.14", "c": "0.22", "d": "-0.58" } ] const grouped = array.reduce((acc, curr) => { for(let key in curr) { if(!acc[key]) { acc[key] = [] }else { acc[key].push(curr[key]) } } return acc; }, {}) const output = [] for(let key in grouped) { const obj = {} const integers = grouped[key].map(el => parseFloat(el, 10)) obj["property"] = key obj["minValue"] = Math.min(...integers) obj["maxValue"] = Math.max(...integers) obj["avg"] = (integers.reduce((prev, curr) => prev + curr) ) / integers.length; output.push(obj) } console.log(output)