Ruby-on-rails Rails 格式化日期
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Rails formatting date
提问by Arthur
I am posting a date to an API and the required format is as follows:
我向 API 发布日期，所需格式如下：
2014-12-01T01:29:18
I can get the date from the model like so:
我可以像这样从模型中获取日期：
Model.created_at.to_s
That returns:
那返回：
2014-12-01 01:29:18 -0500
How can I use Rails or Ruby to format it like the required format with the T and removing the -0500?
如何使用 Rails 或 Ruby 将其格式化为所需的 T 格式并删除 -0500？
回答by Kirti Thorat
Use
用
Model.created_at.strftime("%FT%T")
where,
在哪里，
%F - The ISO 8601 date format (%Y-%m-%d)
%T - 24-hour time (%H:%M:%S)
Following are some of the frequently used useful list of Dateand Timeformats that you could specify in strftimemethod:
以下是您可以在方法中指定的一些常用的有用列表Date和Time格式strftime：
Date (Year, Month, Day):
%Y - Year with century (can be negative, 4 digits at least)
-0001, 0000, 1995, 2009, 14292, etc.
%C - year / 100 (round down. 20 in 2009)
%y - year % 100 (00..99)
%m - Month of the year, zero-padded (01..12)
%_m blank-padded ( 1..12)
%-m no-padded (1..12)
%B - The full month name (``January'')
%^B uppercased (``JANUARY'')
%b - The abbreviated month name (``Jan'')
%^b uppercased (``JAN'')
%h - Equivalent to %b
%d - Day of the month, zero-padded (01..31)
%-d no-padded (1..31)
%e - Day of the month, blank-padded ( 1..31)
%j - Day of the year (001..366)
Time (Hour, Minute, Second, Subsecond):
%H - Hour of the day, 24-hour clock, zero-padded (00..23)
%k - Hour of the day, 24-hour clock, blank-padded ( 0..23)
%I - Hour of the day, 12-hour clock, zero-padded (01..12)
%l - Hour of the day, 12-hour clock, blank-padded ( 1..12)
%P - Meridian indicator, lowercase (``am'' or ``pm'')
%p - Meridian indicator, uppercase (``AM'' or ``PM'')
%M - Minute of the hour (00..59)
%S - Second of the minute (00..59)
%L - Millisecond of the second (000..999)
%N - Fractional seconds digits, default is 9 digits (nanosecond)
%3N millisecond (3 digits)
%6N microsecond (6 digits)
%9N nanosecond (9 digits)
%12N picosecond (12 digits)
For the complete listof formats for strftimemethod please visit APIDock
有关方法格式的完整列表，strftime请访问APIDock
回答by BWStearns
Try this:
尝试这个：
created_at.strftime('%FT%T')
It's a time formatting function which provides you a way to present the string representation of the date. (http://ruby-doc.org/core-2.2.1/Time.html#method-i-strftime).
这是一个时间格式化函数，它为您提供了一种呈现日期字符串表示的方法。（http://ruby-doc.org/core-2.2.1/Time.html#method-i-strftime）。
From APIdock:
来自 APIdock：
%Y%m%d => 20071119 Calendar date (basic)
%F => 2007-11-19 Calendar date (extended)
%Y-%m => 2007-11 Calendar date, reduced accuracy, specific month
%Y => 2007 Calendar date, reduced accuracy, specific year
%C => 20 Calendar date, reduced accuracy, specific century
%Y%j => 2007323 Ordinal date (basic)
%Y-%j => 2007-323 Ordinal date (extended)
%GW%V%u => 2007W471 Week date (basic)
%G-W%V-%u => 2007-W47-1 Week date (extended)
%GW%V => 2007W47 Week date, reduced accuracy, specific week (basic)
%G-W%V => 2007-W47 Week date, reduced accuracy, specific week (extended)
%H%M%S => 083748 Local time (basic)
%T => 08:37:48 Local time (extended)
%H%M => 0837 Local time, reduced accuracy, specific minute (basic)
%H:%M => 08:37 Local time, reduced accuracy, specific minute (extended)
%H => 08 Local time, reduced accuracy, specific hour
%H%M%S,%L => 083748,000 Local time with decimal fraction, comma as decimal sign (basic)
%T,%L => 08:37:48,000 Local time with decimal fraction, comma as decimal sign (extended)
%H%M%S.%L => 083748.000 Local time with decimal fraction, full stop as decimal sign (basic)
%T.%L => 08:37:48.000 Local time with decimal fraction, full stop as decimal sign (extended)
%H%M%S%z => 083748-0600 Local time and the difference from UTC (basic)
%T%:z => 08:37:48-06:00 Local time and the difference from UTC (extended)
%Y%m%dT%H%M%S%z => 20071119T083748-0600 Date and time of day for calendar date (basic)
%FT%T%:z => 2007-11-19T08:37:48-06:00 Date and time of day for calendar date (extended)
%Y%jT%H%M%S%z => 2007323T083748-0600 Date and time of day for ordinal date (basic)
%Y-%jT%T%:z => 2007-323T08:37:48-06:00 Date and time of day for ordinal date (extended)
%GW%V%uT%H%M%S%z => 2007W471T083748-0600 Date and time of day for week date (basic)
%G-W%V-%uT%T%:z => 2007-W47-1T08:37:48-06:00 Date and time of day for week date (extended)
%Y%m%dT%H%M => 20071119T0837 Calendar date and local time (basic)
%FT%R => 2007-11-19T08:37 Calendar date and local time (extended)
%Y%jT%H%MZ => 2007323T0837Z Ordinal date and UTC of day (basic)
%Y-%jT%RZ => 2007-323T08:37Z Ordinal date and UTC of day (extended)
%GW%V%uT%H%M%z => 2007W471T0837-0600 Week date and local time and difference from UTC (basic)
%G-W%V-%uT%R%:z => 2007-W47-1T08:37-06:00 Week date and local time and difference from UTC (extended)
回答by NoDisplayName
Create an initializer for it:
为其创建一个初始化程序：
# config/initializers/time_formats.rb
Add something like this to it:
添加这样的东西：
Time::DATE_FORMATS[:custom_datetime] = "%d.%m.%Y"
And then use it the following way:
然后按以下方式使用它：
post.updated_at.to_s(:custom_datetime)
?? Your have to restart rails server for this to work.
?? 您必须重新启动 rails 服务器才能使其工作。
Check the documentation for more information: http://api.rubyonrails.org/v5.1/classes/DateTime.html#method-i-to_formatted_s
查看文档以获取更多信息：http: //api.rubyonrails.org/v5.1/classes/DateTime.html#method-i-to_formatted_s
回答by Andres Ehrenpreis
Since I18nis the Rails core feature starting from version 2.2you can use its localize-method. By applying the forementioned strftime %-variablesyou can specify the desired format under config/locales/en.yml(or whatever language), in your case like this:
由于I18n是从2.2 版开始的 Rails 核心功能，您可以使用它的localize-方法。通过应用上述strftime % 变量，您可以在config/locales/en.yml（或任何语言）下指定所需的格式，在您的情况下，如下所示：
time:
formats:
default: '%FT%T'
Or if you want to use this kind of format in a few specific places you can refer it as a variable like this
或者，如果您想在一些特定的地方使用这种格式，您可以将其称为这样的变量
time:
formats:
specific_format: '%FT%T'
After that you can use it in your views like this:
之后，您可以在您的视图中使用它，如下所示：
l(Mode.last.created_at, format: :specific_format)
