[转]ruby 时间日期处理
转自
http://foyoto.iteye.com/blog/941654
1.当前时间
Time.new 或Time.now
2.Time类的方法mktime(同义方法是local方法)来根据传入的参数生成时间对象，并且它使用的是当前的时间
Java代码
t1 = Time.mktime(2001) => Mon Jan 01 00:00:00 +0800 2001
t2 = Time.mktime(2001,3) => Thu Mar 01 00:00:00 +0800 2001
t3 = Time.mktime(2001,3,15) => Thu Mar 15 00:00:00 +0800 2001
t4 = Time.mktime(2001,3,15,21) => Thu Mar 15 21:00:00 +0800 2001
t5 = Time.mktime(2001,3,15,21,30) => Thu Mar 15 21:30:00 +0800 2001
t6 = Time.mktime(2001,3,15,21,30,15) => Thu Mar 15 21:30:15 +0800 2001
t1 = Time.mktime(2001) => Mon Jan 01 00:00:00 +0800 2001
t2 = Time.mktime(2001,3) => Thu Mar 01 00:00:00 +0800 2001
t3 = Time.mktime(2001,3,15) => Thu Mar 15 00:00:00 +0800 2001
t4 = Time.mktime(2001,3,15,21) => Thu Mar 15 21:00:00 +0800 2001
t5 = Time.mktime(2001,3,15,21,30) => Thu Mar 15 21:30:00 +0800 2001
t6 = Time.mktime(2001,3,15,21,30,15) => Thu Mar 15 21:30:15 +0800 2001
3.Time.gm(同义方法是Time.utc)方法基本上和上面的mktime用法相同，但它使用的是GMT或 UTC时区
Java代码
t8 = Time.gm(2001,3,15,21,30,15) => Thu Mar 15 21:30:15 UTC 2001
t9 = Time.utc(2001,3,15,21,30,15) => Thu Mar 15 21:30:15 UTC 2001
t8 = Time.gm(2001,3,15,21,30,15) => Thu Mar 15 21:30:15 UTC 2001
t9 = Time.utc(2001,3,15,21,30,15) => Thu Mar 15 21:30:15 UTC 2001
4.Time对象的to_a方法
生成的时间对象有一个to_a方法，可以把时间相关一信息转化成一个数组。
Java代码
t9.to_a => [15, 30, 21, 15, 3, 2001, 4, 74, false, "UTC"]
t9.to_a => [15, 30, 21, 15, 3, 2001, 4, 74, false, "UTC"]
数组中存放的信息格式如下：
seconds,
minutes,
hours,
day,
month,
year,
day of week (0..6),
day of year (1..366),
daylight saving (true or false),
and time zone (as a string)
5.使用秒数来创建日期
在内部，日期存储为一个整数，代表从1970年开始到当前的秒数，我们可以获取这么秒数或则利用这个秒数来创建日期：
Java代码
epoch = Time.at(0) # Find the epoch (Thu Jan 01 08:00:00 +0800 1970)
newmil = Time.at(978307200) # Happy New Millennium! (Mon Jan 01 08:00:00 +0800 2001)
now = Time.now # Sat Mar 05 16:25:00 +0800 2011
sec = now.to_i # 1299313500
epoch = Time.at(0) # Find the epoch (Thu Jan 01 08:00:00 +0800 1970)
newmil = Time.at(978307200) # Happy New Millennium! (Mon Jan 01 08:00:00 +0800 2001)
now = Time.now # Sat Mar 05 16:25:00 +0800 2011
sec = now.to_i # 1299313500
6.格式化时间
Java代码
<PRE class=java name="code">time.strftime( string ) => string</PRE>
<BR> t = Time.now => Sat Mar 05 16:36:18 +0800 2011
<BR> t.strftime("%Y/%m/%d %H:%M") => "2011/03/05 16:36"
<BR> t.strftime("%Y/%m/%d") => "2011/03/05"
Java代码 time.strftime( string ) => string time.strftime( string ) => string
t = Time.now => Sat Mar 05 16:36:18 +0800 2011
t.strftime("%Y/%m/%d %H:%M") => "2011/03/05 16:36"
t.strftime("%Y/%m/%d") => "2011/03/05"
所有strftime方法中可用的格式化符号：
%a 星期的缩写，如Wed
%A 星期的全称，如Wednesday
%U 本星期在全年中所属的周数
%W
%H 小时(24小时制)
%M 分钟
%S 秒
%I 小时(12小时制)
%p PM 或 AM
%b 月份的缩写,如 Jan
%B 月份的全称,如 January
%c 本地日期和时间，如 06/14/07 16:43:49
%d 日期 (1..31)
%j 本日在一年中所属的天 (1..366)
%m 月份 (1..12)
%w 星期的数字形式 (0..6)
%x 本地日期，如 06/14/07
%Y 本地时间，如 16:43:49
%y 2位的年份表示，如07
%Y 4位的年份表示，如2007
%Z 时区名，如"中国标准时间"
%% 字面符号%
7.Time对象的常用方法
Java代码
t = Time.now
t= Time.now=> Sat Mar 05 16:57:35 +0800 2011
t.year=> 2011#年
t.month => 3#月
t.day => 5#日
t.hour => 16#小时
t.min => 57#分钟
t.sec => 35#秒
t.wday => 6#表示星期六，星期天为0
t.yday => 64#一年的第几天
t = Time.now
t= Time.now=> Sat Mar 05 16:57:35 +0800 2011
t.year=> 2011#年
t.month => 3#月
t.day => 5#日
t.hour => 16#小时
t.min => 57#分钟
t.sec => 35#秒
t.wday => 6#表示星期六，星期天为0
t.yday => 64#一年的第几天
还有to_a, to_i,to_s ....更多参考http://ruby-doc.org/core/
8.rails日期和时间的扩展
Java代码
now = Time.now => Sat Mar 05 17:09:55 +0800 2011
now.to_date => Sat, 05 Mar 2011
now.to_s => "Sat Mar 05 17:09:55 +0800 2011"
now.to_s(:short) => "05 Mar 17:09"
now.to_s(:long) => "March 05, 2011 17:09"
now.to_s(:db) => "2011-03-05 17:09:55"
now.to_s(:rfc822) => "Sat, 05 Mar 2011 17:09:55 +0800"
now.at_beginning_of_day => Sat Mar 05 00:00:00 +0800 2011
now.at_beginning_of_month => Tue Mar 01 00:00:00 +0800 2011
now.at_beginning_of_week => Mon Feb 28 00:00:00 +0800 2011
now.at_beginning_of_quarter => Sat Jan 01 00:00:00 +0800 2011
now.at_beginning_of_year => Sat Jan 01 00:00:00 +0800 2011
now.at_midnight => Sat Mar 05 00:00:00 +0800 2011
now.change(:hour => 13) => Sat Mar 05 13:00:00 +0800 2011
now.last_month => Sat Feb 05 17:09:55 +0800 2011
now.last_year => Fri Mar 05 17:09:55 +0800 2010
now.midnight => Sat Mar 05 00:00:00 +0800 2011
now.monday => Mon Feb 28 00:00:00 +0800 2011
now.months_ago(2) => Wed Jan 05 17:09:55 +0800 2011
now.months_ago(1) => Sat Feb 05 17:09:55 +0800 2011
now.months_ago(3) => Sun Dec 05 17:09:55 +0800 2010
now.months_since(2) => Thu May 05 17:09:55 +0800 2011
now.next_week => Mon Mar 07 00:00:00 +0800 2011
now.next_year => Mon Mar 05 17:09:55 +0800 2012
now.seconds_since_midnight => 61795.249
now.since(7200) => Sat Mar 05 19:09:55 +0800 2011
now.tomorrow => Sun Mar 06 17:09:55 +0800 2011
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