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一种将数组转换为对象数组的有效方法

object arrays javascript

Hussain Ali Akbar · 技术社区 · 6 年前

我有一个接受两个参数的函数: 阵列

["id","name","age",...]

和另一个数组暗礁其中包含这些字段的数据:

 [["1", "john", "10"],["2", "Jane", "11"],["3", "John Doe", "12"],...]

[{id: "1", name: "john", age: "10"},{id: 2", name: "jane", age: "11"},{id: "3", name: "John doe", age: "12"}, ...]

功能如下:

const arrayOfArraysToArrayOfObjects = (csvFields, csvRows) => {
        const data = csvRows.map((row) => {
            let obj = {};
            csvFields.forEach((field, index) => {
                obj[field] = row[index];
            });
            return obj;
        });
        return data;
    };


    const csvFields = ["id","name","age"];
    const csvRows = [["1", "john", "10"],["2", "Jane", "11"],["3", "John Doe", "12"]];
    const data = arrayOfArraysToArrayOfObjects(csvFields, csvRows);
    console.log(data);

问题是,这个函数不是很有效,而且在处理包含很多行的大型csv文件时会变得非常慢。此外,字段可以根据不同的csv文件而变化,这就是为什么我必须保持它的动态性。

有什么办法使这个功能更有效吗?

谢谢你的帮助!

3 回复 | 直到 6 年前

ÐÐ»ÑÑ ÐÐµÐ»ÐµÐ½Ñ 6 年前

周期比方法快,请参见基准: https://jsperf.com/my-test321321321

const arrayOfArraysToArrayOfObjects = (csvFields, csvRows) => {
  let res = []

  for (let arr of csvRows) {
    let obj = {}
    for (let i = 0; i < arr.length; i++) {
      obj[csvFields[i]] = arr[i]

    }
    res.push(obj)
  }

  return res;
};


const csvFields = ["id","name","age"];
const csvRows = [["1", "john", "10"],["2", "Jane", "11"],["3", "John Doe", "12"]];
const data = arrayOfArraysToArrayOfObjects(csvFields, csvRows);
console.log(data);

CertainPerformance 6 年前

一个可能的改进是迭代数组 csvRows 较小的 阵列( )一次。另外,你可以用 for 相反,与数组方法相比,循环的开销稍小(但可读性较差),因此对于大型文件,循环的性能可能更高:

const arrayOfArraysToArrayOfObjects = (csvFields, csvRows) => {
  const rowLen = csvRows.length;
  const fieldLen = csvFields.length;
  const results = [];
  for (let i = 0; i < rowLen; i++) {
    const row = csvRows[i];
    const obj = {};
    for (let j = 0; j < fieldLen; j++) {
      obj[csvFields[j]] = row[j];
    }
    results.push(obj);
  }
  return results;
};

const csvFields = ["id", "name", "age"];
const csvRows = [
  ["1", "john", "10"],
  ["2", "Jane", "11"],
  ["3", "John Doe", "12"]
];
const data = arrayOfArraysToArrayOfObjects(csvFields, csvRows);
console.log(data);

Nina Scholz 6 年前

Object.assign 分散单个键/值对象。

const
    arrayOfArraysToArrayOfObjects = (csvFields, csvRows) => 
        csvRows.map(row => Object.assign(...csvFields.map((k, i) => ({ [k]: row[i] })))),
    csvFields = ["id", "name", "age"],
    csvRows = [["1", "john", "10"], ["2", "Jane", "11"], ["3", "John Doe", "12"]],
    data = arrayOfArraysToArrayOfObjects(csvFields, csvRows);

console.log(data);

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