Feature #14877


Calculate age in Date class

Added by derosm2 (Mike DeRosa) over 3 years ago. Updated about 3 years ago.

Target version:


Seems like there's enough complexity in determining the right values and it's something a ton of apps have to address. I've seen a bunch of StackOverflow and other blog posts attempt to address this, not all of them accurately.

Specifically age would calculate the number of years since a person's birthdate (or how old they are).

So if today is 2018, 6, 28:, 3, 6).age #=> 2, 6, 29).age #=> 1

Updated by shevegen (Robert A. Heiler) over 3 years ago

I am not sure if .age() is a "proper name" or not, so I can't really decide
on that. But I specifically wanted to add two things:

a) not all names necessarily fit towards the ruby object model as-is. Ultimately
you have to ask matz about what fits and what does not fit, but several methods
in the active* ecosystem (the gems) do not make a lot of sense from a "pure"
OOP point of view, in my opinion. That is not to say that these methods never
make sense, mind you (when I suggested ... I think it was .append() or something,
I was not even aware of the active* ecosystem; I only noticed that from a twitter
message how ruby core adds active* stuff ... but I don't use rails etc.. so I
came from a completely different point of view, yet the suggestion seems to
have made sense to matz back then.)

So TL;DR, I think one has to decide on a case-by-case basis whether it fits or
not, API-wise that is.

b) as for your other comment, in regards to StackOverflow, but even more importantly,
what people use with ruby, I actually agree. I think if people keep on having the
same issue over and over again, it may be where the core of ruby could be improved.

Date/Time related stuff is something that I feel is coming up every now and then,
so in this general area I agree - also because I think it is something lots of
people use ruby with.

By the way, it may also help to add a description what the method .age() does,
because with a missing description, others have to fill in so it adds to their
burden of implementation. It's much easier for the core team to add methods
when there is a clear documentation associated with it - but it is your suggestion,
not mine, feel free to proceed in any way that you see fit.

I personally use the "poor man's approach", always calculating in seconds. :P

Actions #2

Updated by derosm2 (Mike DeRosa) over 3 years ago

  • Description updated (diff)
Actions #3

Updated by derosm2 (Mike DeRosa) over 3 years ago

  • Description updated (diff)

Updated by derosm2 (Mike DeRosa) over 3 years ago

I actually opened a pull request in Rails to add this to ActiveSupport, but they told me to come here!

Updated by shan (Shannon Skipper) over 3 years ago

derosm2 (Mike DeRosa) wrote:, 3, 6).age #=> 2

It might be nice to be able to specify a unit of time other than year., 3, 6).age #=> 2, 3, 6).age(:year) #=> 2, 3, 6).age(:century) #=> 0 #=> "2018-07-18", 3, 6).age(:month) #=> 28

Units might include :millenia, :century, :decade, :year, :month, :week, :day, :hour, :minute, :second, :millisecond, :microsecond and :nanosecond.

Updated by matz (Yukihiro Matsumoto) about 3 years ago

  • Status changed from Open to Rejected

I don't think the calculation of age from the birthday is not a responsibility of Date class.
There may be a chance for the method for more generic duration calculation of dates/times.



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