Ruby中处理时间的一些基本操作

 获取当前日期和时间:

以下是一个简单的例子，以获得当前的日期和时间：

#!/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

获取组件的日期和时间：

我们可以用 time  对象来获取日期和时间的各个组成部分。下面的例子显示相同的：

#!/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

time.utc，time.gm和time.local函数：

可用于这两个函数以标准格式来格式化日期如下：

# 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) 

下面的例子，在一个数组来获取所有组件按以下格式：

[sec,min,hour,day,month,year,wday,yday,isdst,zone]

尝试以下操作：

#!/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"]

这个数组可以传递给time.utc或time.local函数得到不同的日期格式如下：

#!/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

跟随着的方式来获得内部表示（依赖于平台）历元以来的秒数时间：

# 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

时区和夏令时：

可以使用一个 time 对象来获取相关的所有信息的时区和夏令如下：

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

格式化时间和日期：

有各种各样的方式来格式化日期和时间。下面是一个例子，说明几个：

#!/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

 时间算术：

可以在时间上做简单的算术如下：

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 - now   # => 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
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