在 Ruby on Rails 中将 DateTime 转换为简单的 Date
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Transform DateTime into simple Date in Ruby on Rails
提问by collimarco
I have a datetime column in db that I want to transform into a simple date when I show it to users.
我在 db 中有一个 datetime 列，我想在向用户显示时将其转换为一个简单的日期。
How can I do that?
我怎样才能做到这一点？
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
回答by Ryan McGeary
DateTime#to_datedoes exist with ActiveSupport:
DateTime#to_dateActiveSupport 确实存在：
$ 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
回答by gkrdvl
Hello collimarco :) you can use ruby strftimemethod to create ur own date/time display.
你好 collimarco :) 你可以使用 ruby strftime方法来创建你自己的日期/时间显示。
time.strftime( string ) => string
time.strftime( 字符串 ) => 字符串
%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"
回答by joshaidan
In Ruby 1.9.2 and above they added a .to_date function to DateTime:
在 Ruby 1.9.2 及更高版本中，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
http://ruby-doc.org/stdlib-1.9.2/libdoc/date/rdoc/DateTime.html#method-i-to_date
This instance method doesn't appear to be present in earlier versions like 1.8.7.
此实例方法似乎不存在于 1.8.7 等早期版本中。
回答by Lassi
For old Ruby (1.8.x):
对于旧的 Ruby (1.8.x)：
myDate = Date.parse(myDateTime.to_s)
回答by CrazyCoderMonkey
Try converting the entry to a string first. As long as the database column type is a date it will be formated as a date.
首先尝试将条目转换为字符串。只要数据库列类型是日期，它就会被格式化为日期。
self.date || self.exif_date_time_original.to_s
self.date || self.exif_date_time_original.to_s
回答by Ryan
I recently wrote a gem to simplify this process and to neaten up your views, etc etc.
我最近写了一个 gem 来简化这个过程并整理你的观点等。
Check it out at: http://github.com/platform45/easy_dates
