In Ruby, the date library which includes the DateTime, Date and Time classes. These classes are specially created to work with dates and times in Ruby programs. The main objective of this article is to facilitate the learners with the most common use of these DateTime, Date and Time classes of Ruby language.
In this article you will learn:
- How to access and use the
DateTimeclass in Ruby - Use of
DateTimein Ruby - Getting particular Date, Day, Month and Year in Ruby
DateTimeand its methods in Ruby- Get the difference between two dates and times in Ruby
- Date and Time mathematics or calculation in Ruby
- Ruby Date and Time Formatting Directives or Specifiers
DateTime class which is located inside the Ruby library, you must include this library by using require command.See the example below:
1 2 3 4 | # import date library # date library includes DateTime class require 'date' |
Get current date and time using DateTime class in Ruby
Please see the example given below:
1 2 3 4 5 6 7 8 | # import date library require 'date' # store current date and time in variable x x = DateTime.now # print value of variable x puts x |
Output:
2016-07-02T22:43:26+00:00
Similarly, the use of Time class will also produce the same result as shown in the example below:
1 2 3 | t = Time.now puts t |
Output:
2016-07-02 22:41:54 +0000
Create a new Date Object from Day, Month and Year in Ruby
In Ruby, you work with dates using Date class. Every exemplary the Date class includes the year, month and date. You can also get a particular year, month or day. For accessing the particular date object in Ruby see the example below:For accessing the particular the date object in Ruby see the example below:
1 2 3 4 5 6 7 8 | # import date library require 'date' # create a new date object from year, month and day d = Date.new(2016, 06, 29) # print the value of date object puts d |
Output:
2016-06-29
Getting particular Year, Month and Day from Date object in Ruby
see the code below example:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | # import date library require 'date' # create a new date object from year, month and day d = Date.new(2016, 06, 29) # print the value of date object puts d # for getting particular year puts d.year # for getting particular month of that year puts d.month # for getting particular day of that month puts d.day |
Output:
2016-06-29
2016
6
29
Examples of DateTime class and its Methods in Ruby
There are many methods in DateTime class. Such as year, month, day, wday (week day), yday (day of year), zone (time zone) etc. They can be used by Time object. To call them in Ruby please see the code below:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | time = Time.new puts "Current Time : " + time.inspect puts time.year # => this will show the year of the date puts time.month # => will show month of the date puts time.day # => will show day of the date puts time.wday # => will show the day of week: 0 = Sunday and go on puts time.yday # => will show the day of the year (365 days) puts time.hour # => will show 24 hours of clock puts time.min # => total min of hour puts time.sec # => total sec of hour puts time.usec # => this will show the microseconds of that hour puts time.zone # => this will show time zone (UTC) (GMT) |
Output:
Current Time : 2017-07-02 23:00:48 +0000
2017
7
2
0
183
23
0
48
324832
UTC
Get Difference between two dates in Ruby
In Ruby, we can easily get the difference between two particular dates.
1 2 3 4 5 6 7 8 9 | require 'date' start_date = Date.parse "2013-09-14" end_date = Date.parse "2013-06-08" x = start_date - end_date puts x |
Output:
98/1
Note: The above result shows that there is one calculation and in which 98 days difference.
Get Difference between two times in Ruby/Examples of Time Calculation or Mathematics in Ruby
1 2 3 4 5 6 7 8 9 10 11 | now = Time.now # this will show the Current time puts now past = now - 10 # this will show less than 10 sec from current time puts past future = now + 10 # this will show more than 10 sec from current time puts future diff = future - now # this will show the diff in sec in future and current time puts diff |
Output:
2017-07-02 23:08:52 +0000
2017-07-02 23:08:42 +0000
2017-07-02 23:09:02 +0000
10.0
Ruby Date and Time Format Specifiers/Commands
A list of complete Ruby date and time format command is listed below in the table with the explanation.
| Serial No | Format Command | Explanation |
| 1 | %a | The abbreviated 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) – Note that y in lower case |
| 20 | %Y | Year with the century (like 2015, 2017). Note that Y is in upper case |
| 21 | %Z | Time zone name. |
| 22 | %% | Literal % character. |
