找到并从JavaScript中的数组中删除嵌套的元素？ 您可以使用Javascript的forEach有效地做到这一点

问题描述

我下面有一个json

[
  {
    "monthlyData": [
      {
        "dateYear": "2020-07","data": [
          {
            "id": "45bf4792-c5a5-44ed-b7e8-57557c4f30ee","date": "2020-07-13T00:00:00.000Z","transactionId": "160","amount": 70,"active": 1,"createdAt": "2020-07-14T02:55:43.988Z","updatedAt": "2020-08-14T02:55:43.988Z","version": 1
          }
        ]
      }
    ],"hashId": "4"
  },{
    "monthlyData": [
      {
        "dateYear": "2020-08","data": [
          {
            "id": "38fe3c68-e6aa-4c57-b4d7-dc6c4f597269","date": "2020-08-13T00:00:00.000Z","transactionId": "146","createdAt": "2020-08-14T02:55:43.988Z","hashId": "5"
  }
]

我有一个数组，其中月份-年份的列表为

let datesArr = ['2020-08','2020-09','2020-10','2020-11','2020-07']

现在，我想从datesArr中一个接一个地选择一个日期，并确定日期是否与整个JSON数组中的dateYear列匹配。应该为这些日期匹配创建JSON数组的副本。我只想保留日期匹配的那些对象。

解决方法

您可以使用Javascript的forEach有效地做到这一点

下面的代码提取您所需的信息。

h = randn(64,1); 

H = zeros(256,256); 
for l= 1:256
    for p = 1 : 256 
        if (l-p <= 64 && l-p >= 0)  
            H(l,p) = h(l-p); 
        end 
    end 
end

  

具体取决于您希望它如何编译结果，这与您的问题并不矛盾，您应该能够根据需要进行调整。

没有您想要的输出示例，我们所能做的就是猜测您的意思。

,

您可以使用 array.filter

let originalArray = [
    {
        "monthlyData": [
            {
                "dateYear": "2020-07","data": [
                    {
                        "id": "45bf4792-c5a5-44ed-b7e8-57557c4f30ee","date": "2020-07-13T00:00:00.000Z","transactionId": "160","amount": 70,"active": 1,"createdAt": "2020-07-14T02:55:43.988Z","updatedAt": "2020-08-14T02:55:43.988Z","version": 1
                    }
                ]
            }
        ],"hashId": "4"
    },{
        "monthlyData": [
            {
                "dateYear": "2020-08","data": [
                    {
                        "id": "38fe3c68-e6aa-4c57-b4d7-dc6c4f597269","date": "2020-08-13T00:00:00.000Z","transactionId": "146","createdAt": "2020-08-14T02:55:43.988Z","hashId": "5"
    }
];

let datesArr = ['2020-08','2020-09','2020-10','2020-11'];

let filtered = originalArray.filter(value => {
    value.monthlyData = value.monthlyData.filter(md => {
        return datesArr.includes(md.dateYear);
    })
    return value.monthlyData.length > 0;
})

console.log(JSON.stringify(filtered))

此示例将在下面显示此内容（如果您要这样做的话）：

[
  {
    "monthlyData": [
      {
        "dateYear": "2020-08","data": [
          {
            "id": "38fe3c68-e6aa-4c57-b4d7-dc6c4f597269","version": 1
          }
        ]
      }
    ],"hashId": "5"
  }
]

编辑日期对象比较

如果dateArr像

let datesArr = [new Date('2020-08'),new Date('2020-09')];

您可以在第二个过滤器内使用 array.some

let filtered = originalArray.filter(value => {
    value.monthlyData = value.monthlyData.filter(md => {
        return datesArr.some(value1 => value1.getTime() === new Date(md.dateYear).getTime());
    })
    return value.monthlyData.length > 0;
})

当然，如果原始数组也具有Date对象，则可以丢弃 new Date(md.dateYear).getTime()改用md.dateYear.getTime()

编辑您的评论：

我需要将那些日期添加到与之不匹配的monthData中 dateArray，数据为空。我该怎么办。

您可以为此使用以下代码

let newArr = []
datesArr.forEach(date => {
    let element = originalArray.find(value => {
        value.monthlyData = value.monthlyData.filter(md => {
            return date === md.dateYear;
        })
        return value.monthlyData.length > 0;
    })

    if (!element){
        element = {
            "monthlyData": [
                {
                    "dateYear": date,"data": []
                }
            ],"hashId": "something?"
        }
    }else {
        // make a clone
        element = JSON.parse(JSON.stringify(element))
    }
    newArr.push(element);
})