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函数输出替换主JSON字符串的前两行

group-by json arrays javascript
  •  0
  • Datacrawler  · 技术社区  · 6 年前

    我有一个JSON查询,我正在使用 console.log 呈现方式: 

    var json_data = {"headers":["Month","Value","Number"],"rows":[["2018-10-01 00:00:00.0","one",209],["2018-09-01 00:00:00.0","one",274],["2018-09-01 00:00:00.0","five",183],["2018-10-01 00:00:00.0","five",164],["2018-09-01 00:00:00.0","four",214],["2018-10-01 00:00:00.0","four",192],["2018-09-01 00:00:00.0","three",128],["2018-10-01 00:00:00.0","three",125],["2018-09-01 00:00:00.0","two",199],["2018-10-01 00:00:00.0","two",169],["2018-09-01 00:00:00.0","seven",10541],["2018-10-01 00:00:00.0","seven",6139],["2018-10-01 00:00:00.0","six",169],["2018-09-01 00:00:00.0","six",233]]};

document.getElementById("original").innerHTML = json_data.rows;
 
    <div style="background:yellow; "id="original"></div>
<div style="background:red;" id="output"></div>

    “一个” 我有两个号码( 和 ).

    然后我使用一个函数来groupby,它可以正常工作(输出)。我的问题是当我使用 控制台.log 对于初始的json\u数据查询,前两行是不同的。似乎我的函数用输出的行(红色)替换了前两行。函数如下: 

        function initialGroupBy(rows) {
  const 
    rowMap = new Map(),
    result = [],
    dataTemp = [];

  // Iterate over the rows.
  rows.forEach(row => {

    const
      // Create a key, it is the first elements joined together.
      key = row.slice(0,1).join();

    // Check if the Map has the generated key...
    if (rowMap.has(key)) {
      // The map has the key, we need to add up the values
      const
        // Get the value for the current key.
        storedRow = rowMap.get(key);
        // Add the value of the current row to the row in the map.
        storedRow[2] += row[2];

    } else {
      // The key doens't exist yet, add the row to the map.
      rowMap.set(key, row);
    }

  });

  // Iterate over all the entries in the map and push each value with the
  // summed up value into the array.
  rowMap.forEach(value => {
    result.push(value);
  });


    for (i = 0; i < result.length; i++) 
    {
    var object2 = {"date": result[i][0].slice(0,7), "num": result[i][2]};
    dataTemp.push(object2);      
    }

    return dataTemp;

}

    可以在此处找到完整的代码段(比较两个代码段中黄色框的前两行): 

    var json_data = {"headers":["Month","Value","Number"],"rows":[["2018-10-01 00:00:00.0","one",209],["2018-09-01 00:00:00.0","one",274],["2018-09-01 00:00:00.0","five",183],["2018-10-01 00:00:00.0","five",164],["2018-09-01 00:00:00.0","four",214],["2018-10-01 00:00:00.0","four",192],["2018-09-01 00:00:00.0","three",128],["2018-10-01 00:00:00.0","three",125],["2018-09-01 00:00:00.0","two",199],["2018-10-01 00:00:00.0","two",169],["2018-09-01 00:00:00.0","seven",10541],["2018-10-01 00:00:00.0","seven",6139],["2018-10-01 00:00:00.0","six",169],["2018-09-01 00:00:00.0","six",233]]};

function initialGroupBy(rows) {
  const 
    rowMap = new Map(),
    result = [],
    dataTemp = [];
    
  // Iterate over the rows.
  rows.forEach(row => {
  
    const
      // Create a key, it is the first elements joined together.
      key = row.slice(0,1).join();
      
    // Check if the Map has the generated key...
    if (rowMap.has(key)) {
      // The map has the key, we need to add up the values
      const
        // Get the value for the current key.
        storedRow = rowMap.get(key);
        // Add the value of the current row to the row in the map.
        storedRow[2] += row[2];
        
    } else {
      // The key doens't exist yet, add the row to the map.
      rowMap.set(key, row);
    }

  });
  
  // Iterate over all the entries in the map and push each value with the
  // summed up value into the array.
  rowMap.forEach(value => {
    result.push(value);
  });
    

	for (i = 0; i < result.length; i++) 
	{
    var object2 = {"date": result[i][0].slice(0,7), "num": result[i][2]};
    dataTemp.push(object2);      
	}

	return dataTemp;

}

const damn = initialGroupBy(json_data.rows);

 
document.getElementById("original").innerHTML = json_data.rows;
document.getElementById("output").innerHTML =JSON.stringify(damn);
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<div style="background:yellow; "id="original"></div>
<br><br>
<div style="background:red;" id="output"></div>

    我试过换衣服 var const JavaScript 这里有箱子吗?

    3 回复  |  直到 6 年前
        1
  •  0
  •   Datacrawler    6 年前

    作为你的 价值 是数组对象,当您将其保存在临时 地图

    所以在一开始 forEach公司 循环,对实际更改原始数组项的值求和。

    解决方案非常简单,只需克隆阵列: 

    rowMap.set(key, row.slice());

    另一种可能是使用不同的数组来保存总数。 

    var json_data = {"headers":["Month","Value","Number"],"rows":[["2018-10-01 00:00:00.0","one",209],["2018-09-01 00:00:00.0","one",274],["2018-09-01 00:00:00.0","five",183],["2018-10-01 00:00:00.0","five",164],["2018-09-01 00:00:00.0","four",214],["2018-10-01 00:00:00.0","four",192],["2018-09-01 00:00:00.0","three",128],["2018-10-01 00:00:00.0","three",125],["2018-09-01 00:00:00.0","two",199],["2018-10-01 00:00:00.0","two",169],["2018-09-01 00:00:00.0","seven",10541],["2018-10-01 00:00:00.0","seven",6139],["2018-10-01 00:00:00.0","six",169],["2018-09-01 00:00:00.0","six",233]]};

function initialGroupBy(rows) {
  const 
    rowMap = new Map(),
    result = [],
    dataTemp = [];
    
  // Iterate over the rows.
  rows.forEach(row => {
  
    const
      // Create a key, it is the first elements joined together.
      key = row.slice(0,1).join();
      
    // Check if the Map has the generated key...
    if (rowMap.has(key)) {
      // The map has the key, we need to add up the values
      const
        // Get the value for the current key.
        storedRow = rowMap.get(key);
        // Add the value of the current row to the row in the map.
        storedRow[2] += row[2];
        
    } else {
      // The key doens't exist yet, add the row to the map.
      rowMap.set(key, row.slice());
    }

  });
  
  // Iterate over all the entries in the map and push each value with the
  // summed up value into the array.
  rowMap.forEach(value => {
    result.push(value);
  });
    

	for (i = 0; i < result.length; i++) 
	{
    var object2 = {"date": result[i][0].slice(0,7), "num": result[i][2]};
    dataTemp.push(object2);      
	}

	return dataTemp;

}

const damn = initialGroupBy(json_data.rows);

 
document.getElementById("original").innerHTML = json_data.rows;
document.getElementById("output").innerHTML =JSON.stringify(damn);
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<div style="background:yellow; "id="original"></div>
<div style="background:red;" id="output"></div>
        2
  •  0
  •   Giorgos Papageorgiou    6 年前

    Link

    B) 您的问题是,您实际上是在编辑initialGroupBy函数中的原始对象。也许是这个 answer

        3
  •  0
  •   Datacrawler    6 年前

    这里应用了不同的逻辑,结果很方便: 

    var json_data = {"headers":["Month","Value","Number"],"rows":[["2018-10-01 00:00:00.0","one",209],["2018-09-01 00:00:00.0","one",274],["2018-09-01 00:00:00.0","five",183],["2018-10-01 00:00:00.0","five",164],["2018-09-01 00:00:00.0","four",214],["2018-10-01 00:00:00.0","four",192],["2018-09-01 00:00:00.0","three",128],["2018-10-01 00:00:00.0","three",125],["2018-09-01 00:00:00.0","two",199],["2018-10-01 00:00:00.0","two",169],["2018-09-01 00:00:00.0","seven",10541],["2018-10-01 00:00:00.0","seven",6139],["2018-10-01 00:00:00.0","six",169],["2018-09-01 00:00:00.0","six",233]]};


function groupBy(accumulator, item) {
const [date,extra,value] = item;

const key = date.slice(0,7);

if(!accumulator[key]){
accumulator[key] = 0
}

accumulator[key] += value;
return accumulator;

}

var damn = json_data.rows.reduce(groupBy,{});

damn = Object.keys(damn).map(function(key){
return {date: key, Value: "Total", num: damn[key]};
})

document.getElementById("original").innerHTML = json_data.rows;
document.getElementById("output").innerHTML =JSON.stringify(damn);
    <div style="background:yellow; "id="original"></div>
<div style="background:red;" id="output"></div>
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