# The ruby way : DateTime calculations?

**URL:** <https://www.ruby-forum.com/t/the-ruby-way-datetime-calculations/51772>\
**Category:** Ruby\
**Created:** [November 21, 2005, 11:51pm UTC](https://www.ruby-forum.com/t/the-ruby-way-datetime-calculations/51772 "2005-11-21T23:51:52Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![peter.fitzgibbons](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/838e76/32.png) [@peter.fitzgibbons](https://www.ruby-forum.com/u/peter.fitzgibbons)\
**Post date:** [November 21, 2005, 11:51pm UTC](https://www.ruby-forum.com/t/the-ruby-way-datetime-calculations/51772/1 "2005-11-21T23:51:52Z")

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Is there an existent lib or such that gives me some date/time  
calculations ?

Time.now - 2.minutes for instance ?

Thanks,

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**Author:** ![peter.fitzgibbons](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/838e76/32.png) [@peter.fitzgibbons](https://www.ruby-forum.com/u/peter.fitzgibbons)\
**Post date:** [November 22, 2005, 12:12am UTC](https://www.ruby-forum.com/t/the-ruby-way-datetime-calculations/51772/2 "2005-11-22T00:12:00Z")

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On Monday 21 November 2005 3:48 pm, Peter F. wrote:

> Is there an existent lib or such that gives me some date/time calculations  
> ?
> 
> Time.now - 2.minutes for instance ?

Time.now - 2 \* 60

or

(some people would argue that this is the best approach)

Minute = 60  
Hour = Minute \* 60  
Day = Hour \* 24  
Time.now - 2 \* Minute

or

The ActiveSupport library for Rails has those sorts of methods defined.

or

I think Facets might have these, too.

or

Roll your own. They are easy to write.

Kirk H.

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**Author:** ![peter.fitzgibbons](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/838e76/32.png) [@peter.fitzgibbons](https://www.ruby-forum.com/u/peter.fitzgibbons)\
**Post date:** [November 22, 2005, 12:16am UTC](https://www.ruby-forum.com/t/the-ruby-way-datetime-calculations/51772/3 "2005-11-22T00:16:02Z")

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On 11/21/05, Peter F. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Is there an existent lib or such that gives me some date/time calculations ?
> 
> Time.now - 2.minutes for instance ?

ActiveSupport, which is part of Rails, has this stuff. Take a look:

[http://api.rubyonrails.com/classes/ActiveSupport/CoreExtensions/Numeric/Time.html#M000234](http://api.rubyonrails.com/classes/ActiveSupport/CoreExtensions/Numeric/Time.html#M000234)

Ryan