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Ruby日期和時間

Time類代表在Ruby中的日期和時間。在係統日期和時間由操作係統提供的功能。這個類來表示日期在1970年之前或2038年以後,這個類在係統上可能無法使用。

本基礎教程將熟悉所有最想要的日期和時間的概念。

  1. 獲取當前日期和時間
  2. 獲取組件的日期和時間
  3. Time.utc,Time.gm 和 Time.local 函數
  4. 時區和夏令時
  5. 格式化時間和日期
  6. 時間格式化指令
  7. 時間算術

獲取當前日期和時間:

以下是一個簡單的例子,以獲得當前的日期和時間:

#!/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

這將產生以下結果:

Current Time : Mon Jun 02 12:02:39 -0700 2008
Current Time : Mon Jun 02 12:02:39 -0700 2008

獲取組件的日期和時間:

我們可以用 Time  對象來獲取日期和時間的各個組成部分。下麵的例子顯示相同的:

#!/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

這將產生以下結果:

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函數:

可用於這兩個函數以標準格式來格式化日期如下:

# 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)  

下麵的例子,在一個數組來獲取所有組件按以下格式:

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

嘗試以下操作:

#!/usr/bin/ruby -w

time = Time.new

values = time.to_a
p values

這將產生以下結果:

[26, 10, 12, 2, 6, 2008, 1, 154, false, "MST"]

這個數組可以傳遞給Time.utc或Time.local函數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)

這將產生以下結果:

Mon Jun 02 12:15:36 UTC 2008

跟隨著的方式來獲得內部表示(依賴於平台)曆元以來的秒數時間:

# 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

時區和夏令時:

可以使用一個 Time 對象來獲取相關的所有信息的時區和夏令如下:

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

格式化時間和日期:

有各種各樣的方式來格式化日期和時間。下麵是一個例子,說明幾個:

#!/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")

這將產生以下結果:

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

時間格式化指令:

使用下表中的這些指令的方法 Time.strftime.

Directive Description
%a The abbreviated weekday name (Sun).
%A The full weekday name (Sunday).
%b The abbreviated month name (Jan).
%B The full month name (January).
%c The preferred local date and time representation.
%d Day of the month (01 to 31).
%H Hour of the day, 24-hour clock (00 to 23).
%I Hour of the day, 12-hour clock (01 to 12).
%j Day of the year (001 to 366).
%m Month of the year (01 to 12).
%M Minute of the hour (00 to 59).
%p Meridian indicator (AM or PM).
%S Second of the minute (00 to 60).
%U Week number of the current year, starting with the first Sunday as the first day of the first week (00 to 53).
%W Week number of the current year, starting with the first Monday as the first day of the first week (00 to 53).
%w Day of the week (Sunday is 0, 0 to 6).
%x Preferred representation for the date alone, no time.
%X Preferred representation for the time alone, no date.
%y Year without a century (00 to 99).
%Y Year with century.
%Z Time zone name.
%% Literal % character.

時間算術:

可以在時間上做簡單的算術如下:

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

這將產生以下結果:

Thu Aug 01 20:57:05 -0700 2013
Thu Aug 01 20:56:55 -0700 2013
Thu Aug 01 20:57:15 -0700 2013
10.0