How to display ages instead of dates of birth, in Ruby on Rails?

Question

Possible Duplicate:
Get person's age in Ruby

I am very new to Ruby on Rails, and I have just created a small program to store people, using their names, dates of birth (dob), genders, etc. However, when I query the people from the database using @persons = Persons.find(:all), and I try to list them, I'd love to display their age, that is, today - persons.dob, rather than their date of birth proper.

Vadim · Answer 1 · 2011-04-10T19:08:09.543

7

today = Date.today
d = Date.new(today.year, dob.month, dob.day)
age = d.year - dob.year - (d > today ? 1 : 0)

edited Apr 10 '11 at 19:08

answered Apr 10 '11 at 17:45

Vadim

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`d < today` will always return true – fl00r Apr 10 '11 at 18:26
how can be birthday's year AFTER today? :) – fl00r Apr 10 '11 at 19:07
1

@fl00r, check again how d is constructed, d is this year's birthday. I did have a problem with the comparison reversed though – Vadim Apr 10 '11 at 19:09
It fails for dob being on Feb 29. Use an extra check for date 29 Feb. Better change every 29 Feb to 28 Feb. – Sachin Apr 25 '17 at 07:50

score 4 · Answer 2 · answered Apr 10 '11 at 18:25

4

def age(dob)
  today = Date.today
  age = today.year - dob.year
  age -= 1 if dob.strftime("%m%d").to_i > today.strftime("%m%d").to_i
  age
end

dob = Date.new(1976, 4, 10)
age(dob)
#=> 35
dob = Date.new(1976, 5, 10)
age(dob)
#=> 34

answered Apr 10 '11 at 18:25

fl00r

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this function will be defined in the controller. However, after @persons = Person.find(:all), my @persons variable is already at the view, and I did not want to include this code at my view, thinking it will break the MVC concept ! – azinyue Apr 12 '11 at 14:38
You should add it into helper as a helper method – fl00r Apr 12 '11 at 14:43

score 3 · Answer 3 · 2011-04-10T19:14:41.257

3

Apologies in advance...I'm still learning Ruby:

require 'date'
dob = Date.new(1976, 7, 4)
now = Date.today
age = ((now - dob) / 365.25).to_i

I'm guessing there's a better way...?

edited Apr 10 '11 at 19:14

answered Apr 10 '11 at 17:34

Edit: 365 wasn't correct. But I'm not satisfied with 365.25. I'm going to upvote Vadim's for that reason. – Apr 10 '11 at 19:15

score 1 · Accepted Answer · answered Apr 10 '11 at 17:51

Rails has a couple of Date-Helpers, among them distance_of_time_in_words: http://api.rubyonrails.org/classes/ActionView/Helpers/DateHelper.html#method-i-distance_of_time_in_words.

As far as I remember it adds an "about x years", so it might be not useful in your particular situation unless you take a look at the source and adapt it.

Otherwise you can calculate with years directly calling Date.today.year (or dob.year).

score -2 · Answer 5 · answered Apr 10 '11 at 17:39

-2

This code seems to work for me with a few test ages

age = ((Date.today - dob).to_i / 365.25).ceil

where you define dob as the date object.

answered Apr 10 '11 at 17:39

Gwilym Kuiper

139
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How to display ages instead of dates of birth, in Ruby on Rails?

5 Answers5