JS日期数组如何按天分组 [英] Array Of JS Dates How To Group By Days

问题描述

我正在尝试找出最优的并且用最少量的循环方式来对此js日期对象的数组进行分组:(注意这是浏览器控制台输出它的实际JS日期如新日期（ ））

I'm trying to figure out the most optimal and with as minimum amount of loops way to group my array of js dates objects from this: (Take a note this is browser console output it's actully real JS dates like new Date())

[Sat Aug 08 2015 08:30:00 GMT+0200 (Central Europe Daylight Time), Sat Aug 08 2015 09:30:00 GMT+0200 (Central Europe Daylight Time), Sun Aug 09 2015 08:30:00 GMT+0200 (Central Europe Daylight Time), Sun Aug 09 2015 09:30:00 GMT+0200 (Central Europe Daylight Time), Mon Aug 10 2015 18:00:00 GMT+0200 (Central Europe Daylight Time), Mon Aug 10 2015 23:00:00 GMT+0200 (Central Europe Daylight Time), Tue Aug 11 2015 18:00:00 GMT+0200 (Central Europe Daylight Time), Tue Aug 11 2015 23:00:00 GMT+0200 (Central Europe Daylight Time), Wed Aug 12 2015 18:00:00 GMT+0200 (Central Europe Daylight Time), Wed Aug 12 2015 23:00:00 GMT+0200 (Central Europe Daylight Time)]

与oragnized数组同一天的每个日期然后我可以在UI8月08日显示它，并在当天显示2或多少日期。

to oragnized array with each date of the same day inside a "chunk" so I can display it on the UI "Aug 08" and show 2 or how many dates inside that day.

例如：

[{day: 'Aug 08', times:[Sat Aug 08 2015 08:30:00 GMT+0200 (Central Europe Daylight Time), Sat Aug 08 2015 09:30:00 GMT+0200 (Central Europe Daylight Time)]}]

我目前认为这样做的方式是

My current way I thought about doing it was

var startDays = _.map(occurences, function (date) {
  return moment(date).startOf('day').format();
});

之后获得独特的日子：

_.uniq(startDays, true)

在我之后得到了独特的日子，另一个循环将同一天添加到这个组，你可以看到，你可能会看到为什么我不喜欢它，这就是为什么我希望得到一些聪明的帮助，因为没有任何问题在我的头上。谢谢。

and after I got the unique days another loop to add the same day to this group as you can see by now you might see why I don't like it and this is why I would love to get some smart help because nothing gets to my head with this. Thank you.

推荐答案

Underscore有 _。groupBy 功能应该完全符合您的要求：

Underscore has the _.groupBy function which should do exactly what you want:

var groups = _.groupBy(occurences, function (date) {
  return moment(date).startOf('day').format();
});

这将返回一个对象，其中每个键都是一天，值是一个包含所有出现次数的数组那天。

This will return an object where each key is a day and the value an array containing all the occurrences for that day.

要将对象转换为与问题中相同形式的数组，您可以使用map：

To transform the object into an array of the same form as in the question you could use map:

var result = _.map(groups, function(group, day){
    return {
        day: day,
        times: group
    }
});

要进行分组，映射和排序，您可以执行以下操作：

To group, map and sort you could do something like:

var occurrenceDay = function(occurrence){
    return moment(occurrence).startOf('day').format();
};

var groupToDay = function(group, day){
    return {
        day: day,
        times: group
    }
};

var result = _.chain(occurences)
    .groupBy(occurrenceDay)
    .map(groupToDay)
    .sortBy('day')
    .value();

这篇关于JS日期数组如何按天分组的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！