📅 最后修改于: 2020-10-16 05:54:02 🧑 作者: Mango
Time类表示Ruby中的日期和时间。它是操作系统提供的系统日期和时间功能的薄薄一层。此类在您的系统上可能无法表示1970年之前或2038年之后的日期。
本章使您熟悉所有最想要的日期和时间概念。
以下是获取当前日期和时间的简单示例-
#!/usr/bin/ruby -w
time1 = Time.new
puts "Current Time : " + time1.inspect
# Time.now is a synonym:
time2 = Time.now
puts "Current Time : " + time2.inspect
这将产生以下结果-
Current Time : Mon Jun 02 12:02:39 -0700 2008
Current Time : Mon Jun 02 12:02:39 -0700 2008
我们可以使用Time对象来获取日期和时间的各个组成部分。以下是显示相同内容的示例-
#!/usr/bin/ruby -w
time = Time.new
# Components of a Time
puts "Current Time : " + time.inspect
puts time.year # => Year of the date
puts time.month # => Month of the date (1 to 12)
puts time.day # => Day of the date (1 to 31 )
puts time.wday # => 0: Day of week: 0 is Sunday
puts time.yday # => 365: Day of year
puts time.hour # => 23: 24-hour clock
puts time.min # => 59
puts time.sec # => 59
puts time.usec # => 999999: microseconds
puts time.zone # => "UTC": timezone name
这将产生以下结果-
Current Time : Mon Jun 02 12:03:08 -0700 2008
2008
6
2
1
154
12
3
8
247476
UTC
这两个功能可用于以以下标准格式格式化日期-
# July 8, 2008
Time.local(2008, 7, 8)
# July 8, 2008, 09:10am, local time
Time.local(2008, 7, 8, 9, 10)
# July 8, 2008, 09:10 UTC
Time.utc(2008, 7, 8, 9, 10)
# July 8, 2008, 09:10:11 GMT (same as UTC)
Time.gm(2008, 7, 8, 9, 10, 11)
以下是以以下格式获取数组中所有组件的示例-
[sec,min,hour,day,month,year,wday,yday,isdst,zone]
尝试以下-
#!/usr/bin/ruby -w
time = Time.new
values = time.to_a
p values
这将产生以下结果-
[26, 10, 12, 2, 6, 2008, 1, 154, false, "MST"]
该数组可以传递给Time.utc或Time.local函数以获取不同的日期格式，如下所示：
#!/usr/bin/ruby -w
time = Time.new
values = time.to_a
puts Time.utc(*values)
这将产生以下结果-
Mon Jun 02 12:15:36 UTC 2008
以下是获取自（平台相关的）时代以来内部以秒表示的时间的方法-
# Returns number of seconds since epoch
time = Time.now.to_i
# Convert number of seconds into Time object.
Time.at(time)
# Returns second since epoch which includes microseconds
time = Time.now.to_f
您可以使用Time对象来获取与时区和夏令时相关的所有信息，如下所示：
time = Time.new
# Here is the interpretation
time.zone # => "UTC": return the timezone
time.utc_offset # => 0: UTC is 0 seconds offset from UTC
time.zone # => "PST" (or whatever your timezone is)
time.isdst # => false: If UTC does not have DST.
time.utc? # => true: if t is in UTC time zone
time.localtime # Convert to local timezone.
time.gmtime # Convert back to UTC.
time.getlocal # Return a new Time object in local zone
time.getutc # Return a new Time object in UTC
有多种格式化日期和时间的方法。这是一个显示几个例子-
#!/usr/bin/ruby -w
time = Time.new
puts time.to_s
puts time.ctime
puts time.localtime
puts time.strftime("%Y-%m-%d %H:%M:%S")
这将产生以下结果-
Mon Jun 02 12:35:19 -0700 2008
Mon Jun 2 12:35:19 2008
Mon Jun 02 12:35:19 -0700 2008
2008-06-02 12:35:19
下表中的这些指令与Time.strftime方法一起使用。
| Sr.No. | Directive & Description |
|---|---|
| 1 |
%a The abbreviated weekday name (Sun). |
| 2 |
%A The full weekday name (Sunday). |
| 3 |
%b The abbreviated month name (Jan). |
| 4 |
%B The full month name (January). |
| 5 |
%c The preferred local date and time representation. |
| 6 |
%d Day of the month (01 to 31). |
| 7 |
%H Hour of the day, 24-hour clock (00 to 23). |
| 8 |
%I Hour of the day, 12-hour clock (01 to 12). |
| 9 |
%j Day of the year (001 to 366). |
| 10 |
%m Month of the year (01 to 12). |
| 11 |
%M Minute of the hour (00 to 59). |
| 12 |
%p Meridian indicator (AM or PM). |
| 13 |
%S Second of the minute (00 to 60). |
| 14 |
%U Week number of the current year, starting with the first Sunday as the first day of the first week (00 to 53). |
| 15 |
%W Week number of the current year, starting with the first Monday as the first day of the first week (00 to 53). |
| 16 |
%w Day of the week (Sunday is 0, 0 to 6). |
| 17 |
%x Preferred representation for the date alone, no time. |
| 18 |
%X Preferred representation for the time alone, no date. |
| 19 |
%y Year without a century (00 to 99). |
| 20 |
%Y Year with century. |
| 21 |
%Z Time zone name. |
| 22 |
%% Literal % character. |
您可以按时间执行简单的算术，如下所示：
now = Time.now # Current time
puts now
past = now - 10 # 10 seconds ago. Time - number => Time
puts past
future = now + 10 # 10 seconds from now Time + number => Time
puts future
diff = future - past # => 10 Time - Time => number of seconds
puts diff
这将产生以下结果-
Thu Aug 01 20:57:05 -0700 2013
Thu Aug 01 20:56:55 -0700 2013
Thu Aug 01 20:57:15 -0700 2013
20.0