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# Ruby Date & Time The **Time** class in Ruby is used to represent dates and times. It is based on the system date and time provided by the operating system. This class may not be able to represent dates before 1970 or after 2038. This tutorial will familiarize you with all the important concepts of dates and times. ## Creating the Current Date and Time Here is a simple example to get the current date and time: ## Example ```ruby #!/usr/bin/ruby -w # -*- coding: UTF-8 -*- time1 = Time.new puts "Current Time : " + time1.inspect # Time.now has the same effect time2 = Time.now puts "Current Time : " + time2.inspect [Try it yourself »](#) The output of the above example will be: Current Time : 2015-09-17 15:23:14 +0800 Current Time : 2015-09-17 15:23:14 +0800 ## Getting Date & Time Components We can use the _Time_ object to get various components of the date and time. See the example below: ## Example ```ruby #!/usr/bin/ruby -w # -*- coding: UTF-8 -*- time = Time.new # Components of a Time puts "Current Time : " + time.inspect puts time.year # => Date of the year puts time.month # => Month of the year (1 to 12) puts time.day # => Day of the month (1 to 31) puts time.wday # => Day of the week (0 is Sunday) puts time.yday # => 365: Day of the 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": Time zone name The output of the above example will be: Current Time : 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 format as shown below: ```ruby # 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) The following example gets all components in an array: [sec,min,hour,day,month,year,wday,yday,isdst,zone] Try the following example: ## Example ```ruby #!/usr/bin/ruby -w time = Time.new values = time.to_a p values The output of the above example will be: [39, 25, 15, 17, 9, 2015, 4, 260, false, "CST"] This array can be passed to _Time.utc_ or _Time.local_ functions to get dates in different formats, as shown below: ## Example ```ruby #!/usr/bin/ruby -w time = Time.new values = time.to_a puts Time.utc(*values) The output of the above example will be: 2015-09-17 15:26:09 UTC Here is another way to get time, in seconds since the epoch (platform-dependent): ```ruby # Returns the number of seconds since the epoch time = Time.now.to_i # Convert seconds back to a Time object Time.at(time) # Returns the number of seconds since the epoch, including microseconds time = Time.now.to_f ## Time Zones and Daylight Saving Time You can use the _Time_ object to get all information related to time zones and daylight saving time, as shown below: ```ruby time = Time.new # Here is the explanation time.zone # => "UTC": returns the time zone time.utc_offset # => 0: UTC is 0 seconds offset from UTC time.zone # => "PST" (or other time zone) time.isdst # => false: If UTC does not have DST (daylight saving time) time.utc? # => true: If in the UTC time zone time.localtime # Convert to the local time zone time.gmtime # Convert back to UTC time.getlocal # Returns a new Time object in the local time zone time.getutc # Returns a new Time object in UTC ## Formatting Time and Date There are multiple ways to format dates and times. The following example demonstrates some of them: ## Example ```ruby #!/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 of the above example will be: 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 Directives The directives listed in the following table are used with the method _Time.strftime_. | Directive | Description | | --- | --- | | %a | Abbreviated weekday name (e.g., Sun). | | %A | Full weekday name (e.g., Sunday). | | %b | Abbreviated month name (e.g., Jan). | | %B | Full month name (e.g., January). | | %c | 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 or 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. | ## Time Arithmetic You can do simple arithmetic with time, as shown below: ```ruby 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 The output of the above example will be: 2015-09-17 15:27:08 +0800 2015-09-17 15:26:58 +0800 2015-09-17 15:27:18 +0800 10.0