一阵到四阵答案

【问题标题】：One array to four arrays一阵到四阵
【发布时间】：2021-04-30 15:04:30
【问题描述】：

我有一个这样的数组：

[{
    "coin": "AION",
    "profit": "3.10",
    "timestamp": "2021-01-26 00:48:01"
},
{
    "coin": "BTC",
    "profit": "77.00",
    "timestamp": "2021-01-26 00:08:04"
},
{
    "coin": "AION",
    "profit": "4.00",
    "timestamp": "2021-01-26 01:08:01"
},
{
    "coin": "BTC",
    "profit": "78.10",
    "timestamp": "2021-01-26 01:08:04"
}]

但我真正需要的是四个（四个是可变的）数组：

array coins:
[{ "AION", "BTC" }]
(variable with extra coins, depending on the first array i already have) > AION, BTC, ETH, ZIL, ARK, etc....

array profit[AION]:
[{ "3.10", "4.00" }]

array profit[BTC]:
[{ "77.00", "78.10" }]
(Variable extra coins/profits) [ETH, ZIL, ARK, etc...]

array timestamp:
[{ "2021-01-26 00:48","2021-01-26 01:08" }]
(Variable extra timestamps depending on first array i already have)

我需要这个来填充 am4charts.LineSeries 的 chartsData 数组。

有人可以帮帮我吗？或者有没有更好的选择？

【问题讨论】：

标签： javascript arrays angularjs multidimensional-array amcharts

【解决方案1】：

这是一种问题，您需要遍历数组的元素并根据某些规则对某些内容进行分组。

这是Array.reduce 的一个很好的用例（虽然你可以用其他方法做同样的事情）

我会做这样的事情：

function indexByCoins(coinsArray) {
    const coinsProfitByCoin = coinsArray.reduce((accumulator, coinInfo) => {
        const { coin, profit, timestamp } = coinInfo

        if (!accumulator[coin]) {
            accumulator[coin] = []
        }

        accumulator[coin].push({ profit, timestamp })
        return accumulator
    }, {})

    return coinsProfitByCoin
}

它并没有完全按照您的要求进行，而是将每个条目的利润与其时间戳分组。所以你会得到：

{
  AION: [
    { profit: '3.10', timestamp: '2021-01-26 00:48:01' },
    { profit: '4.00', timestamp: '2021-01-26 01:08:01' }
  ],
  BTC: [
    { profit: '77.00', timestamp: '2021-01-26 00:08:04' },
    { profit: '78.10', timestamp: '2021-01-26 01:08:04' }
  ]
}

【讨论】：

【解决方案2】：

let arr=[{
    "coin": "AION",
    "profit": "3.10",
    "timestamp": "2021-01-26 00:48:01"
},
{
    "coin": "BTC",
    "profit": "77.00",
    "timestamp": "2021-01-26 00:08:04"
},
{
    "coin": "AION",
    "profit": "4.00",
    "timestamp": "2021-01-26 01:08:01"
},
{
    "coin": "BTC",
    "profit": "78.10",
    "timestamp": "2021-01-26 01:08:04"
}]
let timestampArr=[...new Set(arr.map(item=> item['timestamp']))]
let coinArray=[...new Set(arr.map(item=> item['coin']))]
let AionProfilt=[],btcProfit=[];
arr.map(item=>{
  if(item.coin==='BTC')
    AionProfilt.push(item.profit)
   else
    btcProfit.push(item.profit)
})
console.log(coinArray,AionProfilt,btcProfit,timestampArr)

【讨论】：

【解决方案3】：

您可以使用函数Array.prototype.reduce 进行分组和构建所需的输出。

const array = [{    "coin": "AION",    "profit": "3.10",    "timestamp": "2021-01-26 00:48:01"},{    "coin": "BTC",    "profit": "77.00",    "timestamp": "2021-01-26 00:08:04"},{    "coin": "AION",    "profit": "4.00",    "timestamp": "2021-01-26 01:08:01"},{    "coin": "BTC",    "profit": "78.10",    "timestamp": "2021-01-26 01:08:04"}],
      result = array.reduce((a, {coin, profit, timestamp}) => {
        a.coins.push(coin);
        a.timestamps.push(timestamp);
        (a.profits[coin] || (a.profits[coin] = [])).push(profit);

        return a;
      }, {coins: [], profits: {}, timestamps: []});

console.log(result);

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【讨论】：