如何在 Ruby 中创建一个新的 Date 实例
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How can I create a new Date instance in Ruby
提问by Michael Durrant
How can I create a new Date object in IRB with a given date. The following didn't work.
如何使用给定日期在 IRB 中创建新的 Date 对象。以下没有奏效。
1.9.3p194 :053 > require 'active_support'
=> true
1.9.3p194 :054 > Date.new
=> #<Date:0x9d80730>
1.9.3p194 :055 > Date.parse('12/01/2012')
NoMethodError: undefined method `parse' for Date:Class
from (irb):55
1.9.3p194 :055 > Date.new('12/01/2012')
ArgumentError: wrong number of arguments(1 for 0)
回答by Sébastien Le Callonnec
According to Date documentation:
根据日期文件：
require 'date'
Date.new(2001,2,25) #=> #<Date: 2001-02-25
Date.jd(2451966) #=> #<Date: 2001-02-25
Date.ordinal(2001,56) #=> #<Date: 2001-02-25
Date.commercial(2001,8,7) #=> #<Date: 2001-02-25
Date.parse('2001-02-25') #=> #<Date: 2001-02-25
Date.strptime('25-02-2001', '%d-%m-%Y') #=> #<Date: 2001-02-25
Time.new(2001,2,25).to_date #=> #<Date: 2001-02-25
回答by Houen
1.9.3-p125 :012 > require 'date'
=> true
1.9.3-p125 :013 > Date::new(2012,02,03)
=> #<Date: 2012-02-03 ((2455961j,0s,0n),+0s,2299161j)>
1.9.3-p125 :014 >
回答by jethro
I find the following easier to remember than Date.new:
我发现以下内容比以下内容更容易记住Date.new：
require 'active_support/core_ext/string'
'2019-03-31'.to_date
=> #<Date: 2019-03-21 ((2458564j,0s,0n),+0s,2299161j)>
回答by rossta
If you're trying to get active_support extensions to Date outside of Rails, you'll have to use the core_ext module:
如果您想在 Rails 之外获得对 Date 的 active_support 扩展，则必须使用 core_ext 模块：
require 'active_support/core_ext/date/calculations'
Date.parse('12/01/2012')
=> #<Date: 2012-01-12 ((2455939j,0s,0n),+0s,2299161j)>
More info in this Rails guide: http://edgeguides.rubyonrails.org/active_support_core_extensions.html
此 Rails 指南中的更多信息：http: //edgeguides.rubyonrails.org/active_support_core_extensions.html
回答by Douglas G. Allen
You need to use the date extension from the Ruby Standard Library. Most examples in the docs don't always show you to require it.
您需要使用 Ruby 标准库中的日期扩展。文档中的大多数示例并不总是显示您需要它。
require 'date'
was what you needed. It's not a built in set of Classes or Modules.
是你需要的。它不是一组内置的类或模块。
You get two Classes with that addition,
你得到两个班级，
Date
DateTime
And with that you may now use info found in the docs
有了这个，您现在可以使用文档中的信息
回答by coderGuy
require 'date'
Date::strptime("29-05-2017", "%d-%m-%Y")
So, you need to include this datemodule in your code and then use the method strptimeinside which you may notice for year, I have used capital Ybecause full year is entered as the first parameter of the strptime method. You can use small yif the date is like '29-05-17'.
因此，您需要在代码中包含此日期模块，然后使用strptime方法，您可能会在其中注意到年份，我使用大写Y是因为全年作为 strptime 方法的第一个参数输入。如果日期类似于“29-05-17”，您可以使用小y。
回答by saihgala
Date.strptime("2012-09-21 19:45:48","%Y-%m-%d %H:%M:%S")
