如何使用单个循环从可包含 0 到 7 个元素的数组中生成缺失数据？

发布于 2025-01-11 14:18:24 字数 789 浏览 0 评论 0原文

因此，我有一个 API，它返回过去 7 天分配的水的值，它可以包含一个空数组或一个值，例如：

[
  {
    day: Monday,
    waterDispensed: 40,
  },
  {
    day: Wednesday,
    waterDispensed: 83,
  },
  {
    day: Thursday,
    waterDispensed: 33,
  },
]

假设今天是星期四，我需要一个对象数组来填充过去 7 天缺失的数据as：


[
  {
    day: Friday,  // 25th Feb
    waterDispensed: 0,
  },
  {
    day: Saturday, // 26th Feb
    waterDispensed: 0,
  },
  {
    day: Sunday, // 27th Feb
    waterDispensed: 0,
  },
  {
    day: Monday,
    waterDispensed: 40,
  },  
  {
    day: Tuesday,
    waterDispensed: 0,
  },
  {
    day: Wednesday,
    waterDispensed: 83,
  },
  {
    day: Thursday, // 3rd March
    waterDispensed: 33,
  },
]

考虑到您只需要使用一个循环，您将如何做到这一点？您可以使用条件语句，但不像新手那样。您可以使用数组方法，但应考虑时间复杂度。

原文

So I have an API which returns me the value of water dispensed for the last 7 days and it can contain an empty array or a value such as:

[
  {
    day: Monday,
    waterDispensed: 40,
  },
  {
    day: Wednesday,
    waterDispensed: 83,
  },
  {
    day: Thursday,
    waterDispensed: 33,
  },
]

Assuming today is Thursday and I need an array of objects which would fill missing last 7 days data as:


[
  {
    day: Friday,  // 25th Feb
    waterDispensed: 0,
  },
  {
    day: Saturday, // 26th Feb
    waterDispensed: 0,
  },
  {
    day: Sunday, // 27th Feb
    waterDispensed: 0,
  },
  {
    day: Monday,
    waterDispensed: 40,
  },  
  {
    day: Tuesday,
    waterDispensed: 0,
  },
  {
    day: Wednesday,
    waterDispensed: 83,
  },
  {
    day: Thursday, // 3rd March
    waterDispensed: 33,
  },
]

How would you do this considering that you need to use only one loop? You can use conditional statements but not like a newbie.
You can use array methods but should consider time complexity.

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莫相离 2025-01-18 14:18:24

首先创建一个您需要的工作日数组。为此，您可以使用包含星期几的数组，将其加倍，然后切出与您需要的实际范围相对应的部分。

然后将其转换为值为 0 的对象数组，最后用从响应中获取的对象覆盖该数组中的对象：

const dayNames = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];

function fillWeek(date, data) {
    const weekday = date.getDay();
    const week = dayNames.concat(dayNames).slice(weekday + 1, weekday + 8);
    let result = week.map(day => ({day, waterDispensed: 0 }));
    for (let obj of data) result[week.indexOf(obj.day)] = obj;
    return result;
}

const data = [
  { day: "Monday",    waterDispensed: 40 },
  { day: "Wednesday", waterDispensed: 83 },
  { day: "Thursday",  waterDispensed: 33 },
]
// Let's assume a Thursday (3 March 2022 is a Thursday):
let result = fillWeek(new Date(2022, 2, 3), data);
console.log(result);

First create an array of the week days you need. For this, you can use an array with the days of the week, double it, and then slice out the part that corresponds to the actual range you need.

Then turn that into an object array with 0 values, and finally overwrite the objects in that array with the objects that you got from the response:

const dayNames = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];

function fillWeek(date, data) {
    const weekday = date.getDay();
    const week = dayNames.concat(dayNames).slice(weekday + 1, weekday + 8);
    let result = week.map(day => ({day, waterDispensed: 0 }));
    for (let obj of data) result[week.indexOf(obj.day)] = obj;
    return result;
}

const data = [
  { day: "Monday",    waterDispensed: 40 },
  { day: "Wednesday", waterDispensed: 83 },
  { day: "Thursday",  waterDispensed: 33 },
]
// Let's assume a Thursday (3 March 2022 is a Thursday):
let result = fillWeek(new Date(2022, 2, 3), data);
console.log(result);

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