如何通过设置一周的第一天对一周中的几天进行排序？答案

【问题标题】：How to sort days of week by setting the first day of week?如何通过设置一周的第一天对一周中的几天进行排序？
【发布时间】：2019-10-07 19:00:27
【问题描述】：

如何排序？例如，我希望我一周的第一天是星期一。从此：

周日周一周二周三周四周五周六

我想要这个：

周一周二周三周四周五周六周日

或者我希望我一周的第一天是星期五

那么输出应该是这样的：

周五周六周日周一周二周三周四

let days = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"] //by default first day of week is 0
let firstDayOfWeek = 1 //Mon

days = days.map(m=>{
  //how i can sort this?
  return m
})

【问题讨论】：

标签： javascript arrays

【解决方案1】：

let days = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"] //by default first day of week is 0
let firstDayOfWeek = 2 //Mon

days = days.slice(firstDayOfWeek).concat(days.slice(0, firstDayOfWeek));

console.log(days);

【讨论】：

【解决方案2】：

您可以创建一个包含 2 次迭代 days 数组的数组，然后使用 slice 从任何索引中获取 7 个项目

let days = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]

function getSortedWeek(firstDayOfWeek, days) {
  return [...days, ...days].slice(firstDayOfWeek, firstDayOfWeek + 7)
}

console.log(getSortedWeek(1, days)) // Mon
console.log(getSortedWeek(3, days)) // Wed

代码[...days, ...days] 给出了一个包含 14 个元素的数组，适用于一周中的任何一天。

【讨论】：

我真的很喜欢这个主意

【解决方案3】：

这样试试

let days = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"] //by 
function sortDay(firstDayOfWeek){
  var result = [];
  for(i=0; i<days.length;i++){
    result.push(days[firstDayOfWeek%7])
    firstDayOfWeek++;
  }
  console.log(JSON.stringify(result))
}
sortDay(1)
sortDay(4)

【讨论】：

【解决方案4】：

您可以按天排序

let days = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"] //by default first day of week is 0
let firstDayOfWeek = 2 //Mon

let sorted = days.map((_, i) => days[(i+firstDayOfWeek)%7]);

console.log(sorted)

【讨论】：

【解决方案5】：

您可以取一个天数并通过添加 delta 来调整该值，然后将带有 7 的提醒进行排序。

const
    dayValues = { Sun: 0, Mon: 1, Tue: 2, Wed: 3, Thu: 4, Fri: 5, Sat: 6 },
    days = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"],
    firstDayOfWeek = 1,
    delta = 7 - firstDayOfWeek;

days.sort((a, b) => (dayValues[a] + delta) % 7 - (dayValues[b] + delta) % 7);

console.log(days);

【讨论】：

【解决方案6】：

将firstDayOfWeek 之前的日子切片，并将它们添加到数组的末尾：

const orderByFirstDayOfWeek = (firstDayOfWeek, days) =>
  [...days.slice(firstDayOfWeek), ...days.slice(0, firstDayOfWeek)]

const days = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"] //by default first day of week is 0

console.log(JSON.stringify(orderByFirstDayOfWeek(1, days))) // Mon 1st
console.log(JSON.stringify(orderByFirstDayOfWeek(5, days))) // Fri 1st

【讨论】：