Question

我有一个来自后端的数组数据格式，如下所示：

Array

[{"ckey::"C1","date":"0506","rows":17},
 {"ckey::"C1","date":"0706","rows":7},
 {"ckey::"C2","date":"0706","rows":13},
 {"ckey::"C2","date":"0806","rows":11}]

因此，有几天C1数据存在且几天C2数据。只有一天有C1和C2数据。

我想构建一个类似于C1和C2

的数组

[[17,7,0],[0,13,11]]

C1的第一个嵌套数组，其中第三个值为0，因为对于0806日期，该值不存在。

C2的第二个嵌套数组，其中第一个值为0，因为对于0506日期，该值不存在。

请帮忙。我无法有效地形成阵列。

我认为这将是 O（n ^ 3）解决方案。但请帮助。

更新

这是我的方法，我不能在这里发布代码，但它看起来像这样。

我在单独的数组中得到date values，我过滤了独特的日子。

        angular.forEach(data, function(obj){
            if(timeData.indexOf(obj.date) === -1)
                timeData.push(obj.date);
        });

然后 ckey数组_distinctckeyArray也包含值[“C1”，“C2”]。

angular.forEach(_distinctckeyArray,function(_ckey){
     var _formattedDataArrItem = [];
     angular.forEach(timeData,function(_dateTimeString) {
         var _tempDataVolume = [];

            angular.forEach(_data,function(_dataObj) {
                 if(_dataObj.date === _dateTimeString) {
                     if(_dataObj.ckey === _ckey) {
                         _tempDataVolume.push(_dataObj.rows);

                     }else {
                         _tempDataVolume.push(0);

                     }
                 }
             });
         });

Answer 1

您可以创建一个具有日期属性的对象dates。将值初始化为0

您reduce对数组进行分组。使用Object.values将对象转换为数组。

let arr = [{ckey:"C1","date":"0506","rows":17},{ckey:"C1","date":"0706","rows":7},{ckey:"C2","date":"0706","rows":13},{ckey:"C2","date":"0806","rows":11}];

//Make an object with property dates. assign all property to 0 as initial value.
//Expected output:
//{"0506":0,"0706":0,"0806":0}
let dates = arr.reduce((c, v) => Object.assign(c, {[v.date]: 0}), {});

//Loop thru the array using `reduce`. 
//This is to group the array to object using the ckey as the key
//After grouping, use `Object.values` to convert the object into array
let result = Object.values(arr.reduce((c, {ckey,date,rows}) => {
  c[ckey] = c[ckey] || { ...dates };   //Check if c[ckey] exist. If it does not, "clone" the dates object.
  c[ckey][date] = rows;                //Overide the initial value 0 to the rows value
  return c;
}, {})).map(o => Object.values(o));

console.log(result);

Answer 2

我认为这就是你要找的东西。让我知道。

let data = [{
  'ckey': 'C1',
  'date': '0506',
  'rows': 17
}, {
  'ckey': 'C1',
  'date': '0706',
  'rows': 7
}, {
  'ckey': 'C2',
  'date': '0706',
  'rows': 13
}, {
  'ckey': 'C2',
  'date': '0806',
  'rows': 11
}]

function nested_arrays(array) {
  const result = []

  const obj = {
    c1: [],
    c2: []
  }

  for (let i = 0; i < array.length; i++) {

    if (array[i].ckey === 'C1') {
      obj.c1.push(array[i].rows)
    }
    if (array[i].ckey === 'C2') {
      obj.c2.push(array[i].rows)
    }

  }

  obj.c1.push(0) // set last value to 0
  obj.c2.unshift(0) // set first value to 0

  result.push(obj.c1, obj.c2)

  return result

}

let _tempDataVolume = nested_arrays(data)
console.log(_tempDataVolume) //=> [ [ 17, 7, 0 ], [ 0, 13, 11 ] ]

Answer 3

let arr = [{"ckey::"C1","date":"0506","rows":17},
 {"ckey::"C1","date":"0706","rows":7},
 {"ckey::"C2","date":"0706","rows":13},
 {"ckey::"C2","date":"0806","rows":11}]

    arr.map(res =>{ 
let c1arr = [],
 let c2arr = [], 
    if(res.ckey== 'C1'){  
      c1arr.push(res.rows) 
    }else{ c2arr.push(res.rows) }
     })

let newArrr = []
newArr.push(c1arr);
newArr.push(c2arr);

console.log('arr is',newArr)

将数据解析为JavaScript数组

3 个答案: