Ruby Date & Time
Time class is used to represent dates and times in Ruby. It is based on the system date and time provided by the operating system. This class may not represent dates before 1970 or after 2038.
This tutorial will familiarize you with all important concepts of date and time.
Create the current date and time
The following is a simple example of getting the current date and time:
Example
#!/usr/bin/ruby -w # -*- coding: UTF-8 -*- time1 = Time.new puts "当前时间 : " + time1.inspect # Time.now 功能相同 time2 = Time.now puts "当前时间 : " + time2.inspect
Run Instance»
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The output result of the above example is:
当前时间 : 2015-09-17 15:23:14 +0800 当前时间 : 2015-09-17 15:23:14 +0800
Get Date & Time components
We can use the Time object to get various date and time components. Please look at the following example:
#!/usr/bin/ruby -w # -*- coding: UTF-8 -*- time = Time.new # Time 的组件 puts "当前时间 : " + time.inspect puts time.year # => 日期的年份 puts time.month # => 日期的月份（1 到 12） puts time.day # => 一个月中的第几天（1 到 31） puts time.wday # => 一周中的星期几（0 是星期日） puts time.yday # => 365：一年中的第几天 puts time.hour # => 23：24 小时制 puts time.min # => 59 puts time.sec # => 59 puts time.usec # => 999999：微秒 puts time.zone # => "UTC"：时区名称
The output results of the above example are:
当前时间 : 2015-09-17 15:24:44 +0800 2015 9 17 4 260 15 24 44 921519 CST
Time.utc, Time.gm and Time.local Functions
These functions can be used to format dates in standard formats, as follows:
# July 8, 2008 Time.local(2008, 7, 8) # July 8, 2008, 09:10am，本地时间 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 （与 UTC 相同） Time.gm(2008, 7, 8, 9, 10, 11)
The following example gets all the components in an array:
[sec,min,hour,day,month,year,wday,yday,isdst,zone]
Try the following example:
#!/usr/bin/ruby -w time = Time.new values = time.to_a p values
The output result of the above example is:
[39, 25, 15, 17, 9, 2015, 4, 260, false, "CST"]
This array can be passed to Time.utc or Time. local function to get the different formats of the date, as follows:
#!/usr/bin/ruby -w time = Time.new values = time.to_a puts Time.utc(*values)
The output result of the above example is:
2015-09-17 15:26:09 UTC
The following is the way to get the time, the number of seconds since the epoch (Platform dependent):
# 返回从纪元以来的秒数 time = Time.now.to_i # 把秒数转换为 Time 对象 Time.at(time) # 返回从纪元以来的秒数，包含微妙 time = Time.now.to_f
Time Zone and Daylight Saving Time
You can use the Time object to get all information related to time zone and daylight saving time as follows:
time = Time.new # 这里是解释 time.zone # => "UTC"：返回时区 time.utc_offset # => 0：UTC 是相对于 UTC 的 0 秒偏移 time.zone # => "PST"（或其他时区） time.isdst # => false：如果 UTC 没有 DST（夏令时） time.utc? # => true：如果在 UTC 时区 time.localtime # 转换为本地时区 time.gmtime # 转换回 UTC time.getlocal # 返回本地区中的一个新的 Time 对象 time.getutc # 返回 UTC 中的一个新的 Time 对象
Formatting Time and Date
There are many ways to format dates and times. The following example demonstrates part of it:
#!/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")The output result of the above example is:
2015-09-17 15:26:42 +0800 Thu Sep 17 15:26:42 2015 2015-09-17 15:26:42 +0800 2015-09-17 15:26:42
Time formatting instructions
The instructions and methods listed in the following table## Used together with #Time.strftime.
| Command | Description |
|---|---|
| %a | The abbreviation of the name of the day of the week (such as Sun). |
| %A | The full name of the day of the week (such as Sunday). |
| %b | The abbreviation of the month name (such as Jan). |
| %B | The full name of the month (such as January). |
| %c | Preferred local date and time representation. |
| %d | The day of the month (01 to 31). |
| %H | The hour of the day, 24-hour clock (00 to 23). |
| %I | The hour of the day, 12-hour clock (01 to 12). |
| %j | The day of the year (001 to 366). |
| %m | The month of the year (01 to 12). |
| %M | The minute number of the hour (00 to 59). |
| %p | Meridian indication (AM or PM). |
| %S | The second in minutes (00 or 60). |
| %U | The week number in the current year, starting with the first Sunday (as the first day of the first week) (00 to 53). |
| %W | The week number in the current year, starting with the first Monday (as the first day of the first week) (00 to 53). |
| %w | The day of the week (Sunday is 0, 0 to 6). |
| %x | Preferred representation with only date and no time. |
| %X | Preferred representation with only time and no date. |
| %y | Year representation without century (00 to 99). |
| %Y | Year with century. |
| %Z | Time zone name. |
| %% | % characters. |
Time Algorithm
You can do some simple arithmetic with time, as shown below:
now = Time.now # 当前时间 puts now past = now - 10 # 10 秒之前。Time - number => Time puts past future = now + 10 # 从现在开始 10 秒之后。Time + number => Time puts future diff = future - now # => 10 Time - Time => 秒数 puts diff
The above example runs The output result is:
2015-09-17 15:27:08 +0800 2015-09-17 15:26:58 +0800 2015-09-17 15:27:18 +0800 10.0
