From: Chuck Remes <cremes.devlist@...>
Date: 2010-02-10T04:22:34+09:00
Subject: Re: [Q] algorithm to truncate date to beginning of week?


On Feb 9, 2010, at 12:53 PM, Gary Wright wrote:

> 
> On Feb 9, 2010, at 1:32 PM, Chuck Remes wrote:
> 
>> I need to be able to take any date after Jan 1, 1980 and truncate it to the nearest week.
>> 
>> Example:
>> 
>> Wed Jan 09 17:53:23 -0600 1980 should truncate to Sun Jan 06 00:00:00 -0600 1980
>> 
>> Tue Feb 09 12:29:51 -0600 2010 should truncate to Sun Feb 07 00:00:00 -0600 2010
>> 
>> I've tried all sorts of tricks with modulus (% operator) on the integer representation of time but I can't get anything to work over a range of dates. 
>> 
>> Anyone have any bright ideas?
> 
>>> require 'active_support'
> => true
>>> Time.now.beginning_of_week
> => Mon Feb 08 00:00:00 -0500 2010
>>> 
> 
> It also looks like midnight is considered part of the next day not the previous day as in your example.

Ooh, all of ActiveSupport for a little date manipulation? Nail, meet hammer!

Thanks for this suggestion. I'm going to go with using Date#wday to calculate it though.

cr