Ruby-on-rails 我怎样才能得到昨天的日期？
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How I can get yesterday's date?
提问by Michael Gorsky
How can I get yesterday's date?
我怎样才能得到昨天的日期？
maybe:
也许：
@get_time_now = Time.now.strftime('%m/%d/%Y') / 86400
or
或者
@get_time_now = Time.now.strftime('%m/%d/%Y') - 1.day
or
或者
@get_time_now = Time.now. / 86400
86400 = 1 day, right? (60 * 60 * 24)
86400 = 1 天，对吗？(60*60*24)
回答by Andrew Nesbitt
Rails
导轨
For a date object you could use:
对于日期对象，您可以使用：
Date.yesterday
Or a time object:
或时间对象：
1.day.ago
Ruby
红宝石
Or outside of rails:
或轨道外：
Date.today.prev_day
回答by Koen.
After trying 1.day.agoand variants on it:
在尝试1.day.ago和变体之后：
irb(main):005:0> 1.day.ago
NoMethodError: undefined method `day' for 1:Fixnum
if found that Date.today.prev_dayworks for me:
如果发现Date.today.prev_day对我有用：
irb(main):016:0> Date.today.prev_day
=> #<Date: 2013-04-09 ((2456392j,0s,0n),+0s,2299161j)>
回答by AlejandroVD
Time.now - (3600 * 24) # or Time.now - 86400
or
或者
require 'date'
Date.today.prev_day
回答by shadowbq
Ruby 2.1.2 Native Time
Ruby 2.1.2 本地时间
Answer:
回答：
Time.at(Time.now.to_i - 86400)
Proof:
证明：
2.1.2 :016 > Time.now
=> 2014-07-01 13:36:24 -0400
2.1.2 :017 > Time.now.to_i
=> 1404236192
2.1.2 :018 > Time.now.to_i - 86400
=> 1404149804
2.1.2 :019 > Time.at(Time.now.to_i - 86400)
=> 2014-06-30 13:36:53 -0400
One Day of Seconds.
一日一秒。
86400 = 1 day (60 * 60 * 24)
86400 = 1 天 (60 * 60 * 24)
回答by Sampat Badhe
use DateTime.now - 1
使用 DateTime.now - 1
1.9.3p194 :040 > DateTime.now
=> Mon, 18 Nov 2013 17:58:45 +0530
1.9.3p194 :041 > DateTime.now - 1
=> Sun, 17 Nov 2013 17:58:49 +0530
or DateTime.yesterday
或 DateTime.yesterday
1.9.3p194 :042 > DateTime.yesterday
=> Sun, 17 Nov 2013
or we can use railsadvancemethod for Timeand DateTime
或者我们可以使用railsadvance方法Time和DateTime
1.9.3p194 :043 > Time.now.advance(days: -1)
=> 2013-11-17 17:59:36 +0530
1.9.3p194 :044 > DateTime.now.advance(days: -1)
=> Sun, 17 Nov 2013 17:59:49 +0530
advancemethod also provides this options :years, :months, :weeks, :days, :hours, :minutes, :seconds
advance方法也提供了这个选项 :years, :months, :weeks, :days, :hours, :minutes, :seconds
回答by John Naegle
Use Date.today - 1.days.
使用 Date.today - 1.days。
Date.yesterday depends on the current time and your offset from GMT
Date.yesterday 取决于当前时间和您与 GMT 的偏移量
1.9.3-p125 :100 > Date.today
=> Wed, 29 Feb 2012
1.9.3-p125 :101 > Date.yesterday
=> Wed, 29 Feb 2012
1.9.3-p125 :102 > Date.today - 1.days
=> Tue, 28 Feb 2012
回答by d11wtq
You can just subtract 86400 from a Timeobject to get one day before. If you are using Rails, or have ActiveSupport included, you can replace 86400 with 1.days.
您只需从Time对象中减去 86400即可获得前一天。如果您使用 Rails 或包含 ActiveSupport，则可以将 86400 替换为1.days.
If you're using a Dateobject, and not a Timeobject, just subtract 1 from it.
如果您使用的是一个Date对象，而不是一个Time对象，只需从它减去 1。
To check if one date/time is before/after another, just compare the two objects like you would do for numbers:
要检查一个日期/时间是否在另一个日期/时间之前/之后，只需比较两个对象，就像您对数字所做的那样：
DateTime.parse("2009-05-17T22:38:42-07:00") < DateTime.parse("2009-05-16T22:38:42-07:00")
# => false
