How to calculate how many years passed since a given date in Ruby?

Question

This question was here for other languages, so let here be one for Ruby.

How do I calculate number of complete years that have passed from a given date? As you prob

Answer 1

How about something like:

def years_diff(from_time,to_time)
  (((to_time - from_time).abs)/ (365 * 24 * 60 * 60)).to_i
end

years_diff(Time.now,Time.local(1950,03,22)) #=> 59
years_diff(Time.now,Time.local(2009,03,22)) #=> 0
years_diff(Time.now,Time.local(2008,03,22)) #=> 1

Answer 2

d2.year - d1.year - (d2.month > d1.month || (d2.month == d1.month && d2.day >= d1.day) ? 0 : 1)

Answer 3

How about this:

def age_in_years(date)
  # Difference in years, less one if you have not had a birthday this year.
  today = Date.today
  age = today.year - date.year
  age = age - 1 if [date.day, date.month, today.year].join('/').to_date > Date.today
end

Answer 4

you can use the ruby gem adroit-age

It works for leap years also..

age = AdroitAge.find_age("23/01/1990")

Update

require 'adroit-age'

dob =  Date.new(1990,1,23)
or
dob = "23/01/1990".to_date

age = dob.find_age
#=> 23

Answer 5

An approach that handles leap years

Whenever you're calculating elapsed years since a date, you have to decide how to handle leap year. Here is my approach, which I think is very readable, and is able to take leap years in stride without using any "special case" logic.

def years_completed_since(start_date, end_date)

  if end_date < start_date
    raise ArgumentError.new(
      "End date supplied (#{end_date}) is before start date (#{start_date})"
    )
  end

  years_completed = end_date.year - start_date.year

  unless reached_anniversary_in_year_of(start_date, end_date)
    years_completed -= 1
  end

  years_completed
end

# No special logic required for leap day; its anniversary in a non-leap
# year is considered to have been reached on March 1.
def reached_anniversary_in_year_of(original_date, new_date)
  if new_date.month == original_date.month
    new_date.day >= original_date.day
  else
    new_date.month > original_date.month
  end
end

Answer 6

withing http://github.com/radar/dotiw

Jack is <%= distance_of_time_in_words (Time.now, Time.local(1950,03,22)) %> old.

produce

Jack is 60 years old