# Re: representing a span of time

**URL:** <https://www.ruby-forum.com/t/re-representing-a-span-of-time/67677>\
**Category:** Ruby\
**Created:** [September 6, 2006, 12:18am UTC](https://www.ruby-forum.com/t/re-representing-a-span-of-time/67677 "2006-09-06T00:18:44Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![BergerS\_Daniel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bc8723/32.png) [@BergerS\_Daniel](https://www.ruby-forum.com/u/BergerS_Daniel)\
**Post date:** [September 6, 2006, 12:18am UTC](https://www.ruby-forum.com/t/re-representing-a-span-of-time/67677/1 "2006-09-06T00:18:44Z")

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> x = 64299600.0  
> Brad  
> Are these values seconds since epoch? If so:

irb(main):002:0\> Time.at(1157489583.2798 - 64299600.0)  
=\> Sun Aug 22 09:53:03 MDT 2004

Regards,

Dan

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**Author:** ![BergerS\_Daniel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bc8723/32.png) [@BergerS\_Daniel](https://www.ruby-forum.com/u/BergerS_Daniel)\
**Post date:** [September 6, 2006, 12:25am UTC](https://www.ruby-forum.com/t/re-representing-a-span-of-time/67677/2 "2006-09-06T00:25:37Z")

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Berger, Daniel wrote:

> > x = 64299600.0  
> > Brad  
> > Are these values seconds since epoch? If so:
> 
> irb(main):002:0\> Time.at(1157489583.2798 - 64299600.0)  
> =\> Sun Aug 22 09:53:03 MDT 2004

They are dates in time from Time.mktime(1972, 1, 15, 0, 0, 0) and  
Time.now() represented as floats. Basically, I would like to show the  
difference in a human significant way (years, months, days, etc.)

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<div class="post-metadata">

**Author:** ![BergerS\_Daniel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bc8723/32.png) [@BergerS\_Daniel](https://www.ruby-forum.com/u/BergerS_Daniel)\
**Post date:** [September 6, 2006, 12:46am UTC](https://www.ruby-forum.com/t/re-representing-a-span-of-time/67677/3 "2006-09-06T00:46:46Z")

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On Wed, 6 Sep 2006, Brad T. wrote:

> difference in a human significant way (years, months, days, etc.)  
> They are dates in time from Time.mktime(1972, 1, 15, 0, 0, 0) and  
> Time.now() represented as floats. Basically, I would like to show the

harp:~ \> cat a.rb  
require ‘rubygems’  
require ‘timeunits’

a = Time.mktime(1972, 1, 15, 0, 0, 0).utc  
b = Time.now.utc

delta = b - a

puts delta.decades  
puts delta.years  
puts delta.months  
puts delta.days  
puts delta.minutes  
puts delta.seconds

harp:~ \> ruby a.rb  
3.76567099435856  
37.6567099435856  
451.880519323027  
12652.6545410448  
18219822.5391045  
1093189352.34627

-a

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<div class="post-metadata">

**Author:** ![BergerS\_Daniel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bc8723/32.png) [@BergerS\_Daniel](https://www.ruby-forum.com/u/BergerS_Daniel)\
**Post date:** [September 6, 2006, 3:26am UTC](https://www.ruby-forum.com/t/re-representing-a-span-of-time/67677/4 "2006-09-06T03:26:57Z")

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On Wed, 6 Sep 2006, Brad T. wrote:

> > 37.6567099435856 #This should be 34 years… what is it 37? (2006 - 1972 = 34)  
> > basically because it’s using 28 days months since it’s impossible to  
> > tell when  
> > one says

2.months

whether that should be 28 + 31 vs. 29 + 31 days, etc. so 1.month is  
simply  
equal to 4.weeks and 1.year is 12.months. however, i that is not good  
behaviour so the latest release will give:

```
 harp:~ > cat a.rb
 require 'yaml'
 require 'rubygems'
 require 'timeunits'

 a = Time.mktime(1972, 1, 15, 0, 0, 0).utc
 b = Time.now.utc

 delta = b - a
 y 'delta.years' => delta.years

 seconds_per_day = 1.day
 y 'seconds_per_day' => seconds_per_day

 n_days = 0 and ((a += seconds_per_day and n_days += 1) while a < b)
 y 'n_days' => n_days

 days_per_year = 365
 n_years = Float(n_days)/Float(days_per_year)
 y 'n_years' => n_years

 harp:~ > ruby a.rb
 delta.years: 34.6651137623302
 seconds_per_day: 86400
 n_days: 12653
 n_years: 34.6657534246575

```

i may re-consider the method used to set the delta fields to another  
method.

thanks for the bug report.

-a

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<div class="post-metadata">

**Author:** ![BergerS\_Daniel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bc8723/32.png) [@BergerS\_Daniel](https://www.ruby-forum.com/u/BergerS_Daniel)\
**Post date:** [September 6, 2006, 1:59am UTC](https://www.ruby-forum.com/t/re-representing-a-span-of-time/67677/5 "2006-09-06T01:59:01Z")

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> a = Time.mktime(1972, 1, 15, 0, 0, 0).utc  
> b = Time.now.utc
> 
> delta = b - a
> 
> puts delta.decades  
> puts delta.years
> 
> harp:~ \> ruby a.rb  
> 3.76567099435856  
> 37.6567099435856 #This should be 34 years… what is it 37? (2006 - 1972 = 34)