在DateTime到Time转换中的奇怪的Ruby行为 [英] Weird Ruby Behavior in DateTime to Time conversion

问题描述

我的目标是从DateTime实例获取时间实例

以前在此讨论过，我仍然感到困惑：转换为/从DateTime和Ruby in Ruby

$ b $对于我在irb运行ruby 1.9.3p0（2011-10-30修订版33570）[x86_64-darwin11.2.0]，我的工作完美

  1.9.3p0：001>要求'Date'
 => true 
 1.9.3p0：002>需要'Time'
 => true 
 1.9.3p0：003> t = DateTime.now 
 => ＃< DateTime：2012-07-01T01：57：32 + 05：30（（2456109j，73652s，621060000n），+ 19800s，2299161j）> 
 1.9.3p0：004> t2 = t.to_time 
 => 2012-07-01 01:57:32 +0530 
 1.9.3p0：005> t.class 
 => DateTime 
 1.9.3p0：006> t2.class 
 =>时间
 1.9.3p0：007> 
  

但是在同一个ruby平台上使用rails console v 3.2.3

  1.9.3p0：001> t = DateTime.now 
 => Sun，01 Jul 2012 02:00:00 +0530 
 1.9.3p0：002> t.class 
 => DateTime 
 1.9.3p0：003> t2 = t.to_time 
 => Sun，01七月2012 02:00:00 +0530 
 1.9.3p0> t2.class 
 => DateTime 
  

如何从rails中的DateTime获取Time实例？

解决方案

根据 Rails DateTime.to_time（） 的文档

如果自己有0以外的偏移量，将自动返回不变

要更改为0偏移量，请使用 DateTime.utc（） 。

  1.9.3p194：005> t3 = t2.utc 
 =>星期六，2012年6月30日20:43:21 +0000 
 1.9.3p194：006> t3.offset 
 => （0/1）
 1.9.3p194：007> t4 = t3.to_time 
 => 2012-06-30 20:43:21 UTC 
 1.9.3p194：008> t4.class 
 =>时间
  

My goal is to get a Time instance from a DateTime instance

This has been previously discussed here and I am still confused : Convert to/from DateTime and Time in Ruby

For me in irb running ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-darwin11.2.0], things work perfectly

1.9.3p0 :001 > require 'Date'
 => true 
1.9.3p0 :002 > require 'Time'
 => true 
1.9.3p0 :003 > t=DateTime.now
 => #<DateTime: 2012-07-01T01:57:32+05:30 ((2456109j,73652s,621060000n),+19800s,2299161j)> 
1.9.3p0 :004 > t2=t.to_time
 => 2012-07-01 01:57:32 +0530 
1.9.3p0 :005 > t.class
 => DateTime 
1.9.3p0 :006 > t2.class
 => Time 
1.9.3p0 :007 > 

However when working with rails console v 3.2.3 on same ruby platform

1.9.3p0 :001 > t=DateTime.now
 => Sun, 01 Jul 2012 02:00:00 +0530 
1.9.3p0 :002 > t.class
 => DateTime 
1.9.3p0 :003 > t2=t.to_time
 => Sun, 01 Jul 2012 02:00:00 +0530
1.9.3p0  > t2.class
 => DateTime

What to do to get a Time instance from DateTime in rails?

解决方案

According to the Rails documentation for DateTime.to_time(),

If self has an offset other than 0, self will just be returned unaltered

To change to a 0 offset, use DateTime.utc().

1.9.3p194 :005 > t3=t2.utc
 => Sat, 30 Jun 2012 20:43:21 +0000 
1.9.3p194 :006 > t3.offset
 => (0/1) 
1.9.3p194 :007 > t4=t3.to_time
 => 2012-06-30 20:43:21 UTC 
1.9.3p194 :008 > t4.class
 => Time 

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