未定義的方法`變化 '在IRB控制檯的DateTime

Question

變化（：小時=> 1）在導軌控制檯

irb(main):004:0> dt = DateTime.now 
=> Mon, 10 Dec 2012 15:52:01 -0800 
irb(main):005:0> _.change(:hour => 1) 
=> Mon, 10 Dec 2012 01:00:00 -0800 
irb(main):006:0> 
irb(main):007:0> dt.class 
=> DateTime 
irb(main):008:0> 

工作正常，但將引發「未定義的方法`變化' 在IRB

irb(main):008:0> require 'active_record' 
=> true 
irb(main):009:0> dt = DateTime.now 
=> #<DateTime: 2012-12-10T15:55:14-08:00 (10611097185737/4320000,-1/3,2299161)> 
irb(main):010:0> dt.class 
=> DateTime 
irb(main):011:0> dt.change(:hour => 1) 
NoMethodError: undefined method `change' for #<DateTime:0x53e20a9a> 
     from (irb):11:in `evaluate' 
     from org/jruby/RubyKernel.java:1070:in `eval' 
     from org/jruby/RubyKernel.java:1395:in `loop' 
     from org/jruby/RubyKernel.java:1178:in `catch' 
     from org/jruby/RubyKernel.java:1178:in `catch' 
     from C:\PF\jruby-1.7.0.preview2\bin\irb:13:in `(root)' 
irb(main):012:0> 

」任何建議如何使其工作？

在此先感謝。

Answer 1

Change is an active support method，所以要把它定義，你首先必須要求庫：

>> require 'active_support/all' 
=> true 
>> dt = DateTime.now 
=> Tue, 11 Dec 2012 11:34:54 +0100 
>> dt.change(:hour => 1) 
=> Tue, 11 Dec 2012 01:00:00 +0100 

Answer 2

要獲得有關日期時間功能，只需require 'active_support/time'