如何通过设置一周的第一天来排序一周中的几天？

Question

如何排序？例如，我希望每周的第一天是星期一。从这个：

星期日星期一星期二星期三星期五星期五星期六

我想要这个：

星期一星期二星期三星期四星期五星期六

或者我希望我的第一天是星期五

那么输出中应该是这样：

周五星期六周二周三周三

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
})

Answer 1

切片firstDayOfWeek之前的日子，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

Answer 2

您可以按以下日期获得排序

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)

Answer 3

您可以创建一个包含days数组2次迭代的数组，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，并且可以在一周的任何一天使用。

Answer 4

尝试这样

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)

Answer 5

您可以使用天数并通过添加增量来调整值，然后使用7的铰刀进行排序。

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);

Answer 6

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);