查找去年同一天的日期？ [英] Find date for same day of the week last year?

问题描述

OK，例如今天是02月02日星期二。与去年相当的星期二是2月03日。

OK so for example, today is Tuesday, Feb 02. Well the equivalent "Tuesday" from last year was on Feb 03.

我如何以编程方式找到这个？

How can I find this out programmatically?

谢谢!!

推荐答案

只需我的两分钱。我不喜欢这个想法，第二个答案假设一年52周，它将工作一年，但只是解决这个确切的问题 - 例如。如果你想检查相同的事情回溯10年，它将无法工作。我会这样做：

Just my two cents. I don't like the idea, that the second answer assumes 52 weeks in a year, it will work for a single year, but is a solution to only this exact problem - eg. if you want to check the same thing moving back 10 years it won't work. I'd do it like this:

var today:Date = new Date();    
// Here we store the day of the week            
var currentDay:int = today.day;
trace (today);      
const milisecondsInADay:uint = 1000*60*60*24;
// Here we move back a year, but we can just as well move back 10 years
// or 2 months      
today.fullYear -= 1;
// Find the closest date that is the same day of the week as current day
today.time -= milisecondsInADay*(today.day-currentDay);     
trace (today);

返回：

Tue Feb 2 21:13:18 GMT+0100 2010 
Tue Feb 3 21:13:18 GMT+0100 2009

这篇关于查找去年同一天的日期？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！