在 RubyonRails 中将 DateTime 转换为简单日期

我有一个 db 中的 datetime 列，当我向用户显示它时，我想将它转换为一个简单的日期。

How can I do that?

def shown_date
# to_date does not exist, but is what I am looking for
self.date || self.exif_date_time_original.to_date
end
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最佳答案

ActiveSupport 中确实存在 DateTime#to_date:

$ irb
>> DateTime.new.to_date
NoMethodError: undefined method 'to_date' for #<DateTime: -1/2,0,2299161>
from (irb):1


>> require 'active_support/core_ext'
=> true


>> DateTime.new.to_date
=> Mon, 01 Jan -4712
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Hello collimarco:)您可以使用 ruby 时间方法创建您自己的日期/时间显示。

Strftime (string) = > string

  %a - The abbreviated weekday name (``Sun'')
%A - The  full  weekday  name (``Sunday'')
%b - The abbreviated month name (``Jan'')
%B - The  full  month  name (``January'')
%c - The preferred local date and time representation
%d - Day of the month (01..31)
%H - Hour of the day, 24-hour clock (00..23)
%I - Hour of the day, 12-hour clock (01..12)
%j - Day of the year (001..366)
%m - Month of the year (01..12)
%M - Minute of the hour (00..59)
%p - Meridian indicator (``AM''  or  ``PM'')
%S - Second of the minute (00..60)
%U - Week  number  of the current year,
starting with the first Sunday as the first
day of the first week (00..53)
%W - Week  number  of the current year,
starting with the first Monday as the first
day of the first week (00..53)
%w - Day of the week (Sunday is 0, 0..6)
%x - Preferred representation for the date alone, no time
%X - Preferred representation for the time alone, no date
%y - Year without a century (00..99)
%Y - Year with century
%Z - Time zone name
%% - Literal ``%'' character


t = Time.now
t.strftime("Printed on %m/%d/%Y")   #=> "Printed on 04/09/2003"
t.strftime("at %I:%M%p")            #=> "at 08:56AM"
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我最近编写了一个 gem 来简化这个过程，并整理您的视图等等。

看看 http://github.com/platform45/easy_dates

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在 Ruby 1.9.2及以上版本中，他们向 DateTime 添加了一个. to _ date 函数:

http://ruby-doc.org/stdlib-1.9.2/libdoc/date/rdoc/DateTime.html#method-i-to_date

这个实例方法在1.8.7之类的早期版本中似乎不存在。

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首先尝试将条目转换为字符串。只要数据库列类型是一个日期，它就会被格式化为一个日期。

自拍日期 | | 自拍.exif _ date _ time _ first. to _ s

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对于老 Ruby (1.8.x) :

myDate = Date.parse(myDateTime.to_s)

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