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The Time class represents dates and times in Ruby. It is a thin layer over the system date and time functionality provided by the operating system. This class may be unable on your system to represent dates before 1970 or after 2038.
This chapter makes you familiar with all the most wanted concepts of date and time.
Getting Current Date and Time
Following is the simple example to get current date and time −
#!/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
This will produce the following result −
Current Time : Mon Jun 02 12:02:39 -0700 2008 Current Time : Mon Jun 02 12:02:39 -0700 2008
Getting Components of a Date & Time
We can use Time object to get various components of date and time. Following is the example showing the same −
#!/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
This will produce the following result −
Current Time : Mon Jun 02 12:03:08 -0700 2008 2008 6 2 1 154 12 3 8 247476 UTC
Time.utc, Time.gm and Time.local Functions
These two functions can be used to format date in a standard format as follows −
# 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)
Following is the example to get all the components in an array in the following format −
[sec,min,hour,day,month,year,wday,yday,isdst,zone]
Try the following −
#!/usr/bin/ruby -w time = Time.new values = time.to_a p values
This will generate the following result −
[26, 10, 12, 2, 6, 2008, 1, 154, false, "MST"]
This array could be passed to Time.utc or Time.local functions to get different format of dates as follows −
#!/usr/bin/ruby -w time = Time.new values = time.to_a puts Time.utc(*values)
This will generate the following result −
Mon Jun 02 12:15:36 UTC 2008
Following is the way to get time represented internally as seconds since the (platform-dependent) epoch −
# 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
Timezones and Daylight Savings Time
You can use a Time object to get all the information related to Timezones and daylight savings as follows −
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
Formatting Times and Dates
There are various ways to format date and time. Here is one example showing a few −
#!/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")
This will produce the following result −
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
Time Formatting Directives
These directives in the following table are used with the method Time.strftime.
| 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. |
Time Arithmetic
You can perform simple arithmetic with time as follows −
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
This will produce the following result −
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
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