Question

I have a method on my user model to calculate the user's age and return a human readable string. My user's can be between 1 month old and above so the returned string is different depending on if the person is "2 months old" or "1 year old" or "2 years and 3 months old".

I have reviewed few SO posts to come to this solution. Is there anything I am missing? Leap years? Thank you!

def age
    dob = self.date_of_birth

    # if a date of birth is not nil
    if dob != nil 

      # get current date  
      now = Date.current

      # has person had their birthday yet this year
      had_birthday = ((now.month > dob.month || (now.month == dob.month && now.day >= dob.day)) ? true : false) 

      # if yes then subtract this year from birthday year, if not then also subtract 1 to get how many full years old they are
      years = now.year - dob.year - (had_birthday ? 0 : 1)

      # get the calendar month difference from birthdya calendar month and today's calendar month.  if they have not had their birthdya yet then subtract the difference from 12
      months = had_birthday ? now.month - dob.month : 12 - (now.month - dob.month)

      # for under 1 year olds
      if years == 0
        return months > 1 ? months.to_s + " months old" : months.to_s + " month old"  

      # for 1 year olds
      elsif years == 1
        return months > 1 ? years.to_s + " year and " + months.to_s + " months old" : years.to_s + " year and " + months.to_s + " month old" 

      # for older than 1
      else
        return months > 1 ? years.to_s + " years and " + months.to_s + " months old" : years.to_s + " years and " + months.to_s + " month old"
      end

    # No date of birth saved so can not calculate age
    else
      return "No Date of Birth"
    end
  end

Answer 1

虽然这可能会更好地发布到codereview网站，但我仍然会给你我的想法。

你已经写了一个相当长的方法，可能是一些较小的方法。

首先，我会写一个方法，花费一个月的年数，并将其分成自己的函数。

def readable_age(years, months)
  # for under 1 year olds
  if years == 0
    return months > 1 ? months.to_s + " months old" : months.to_s + " month old"  

  # for 1 year olds
  elsif years == 1
    return months > 1 ? years.to_s + " year and " + months.to_s + " months old" : years.to_s + " year and " + months.to_s + " month old" 

  # for older than 1
  else
    return months > 1 ? years.to_s + " years and " + months.to_s + " months old" : years.to_s + " years and " + months.to_s + " month old"
  end
end

但是，如果你不介意在你的项目中添加一些依赖项，你可以利用actionview gem，你可以利用pluralize函数。

的内容

def readable_age(years, months)
  year_text = ''
  if years == 0
    year_text = "#{years} #{pluralize('year', years)} and "
  end

  "#{year_text}#{pluralize('month', months)} old"
end

现在您的功能可以计算年数和月数。

def age(t)
  dob = self.date_of_birth

  months = (t.year * 12 + t.month) - (dob.year * 12 + dob.month)

  # months / 12 will give the number of years
  # months % 12 will give the number of months
  readable_age(months / 12, 15 % 12)
end

修改

我将日期对象传递到age函数的原因是允许您计算给定时间戳的人的年龄。如果在给定相同输入的情况下产生相同的结果，它还可以更容易地测试函数。

Answer 2

您可以使用time_ago_in_words：

Class.new.extend(ActionView::Helpers::DateHelper).time_ago_in_words(Time.parse("1981-11-20"))
=> "over 34 years"

编辑：我知道，它与您的解决方案没有相同的粒度。只是觉得它可能是一个很好的参考。

Answer 3

基于Rational类的另一个选项和Rails支持的一些日期计算。

% python3  
Python 3.4.3 (default, Mar 26 2015, 22:03:40) 
[GCC 4.9.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> class A:
...     def f(self):
...         nonlocal __x
... 
[4]    19173 segmentation fault (core dumped)  python3

Answer 4

使用Rails助手：

DateHelper = Class.new.extend(ActionView::Helpers::DateHelper)
DateHelper.time_ago_in_words(Time.parse("2002-02-20"))
=> "almost 15 years"

http://api.rubyonrails.org/classes/ActionView/Helpers/DateHelper.html#method-i-time_ago_in_words

Ruby age method using date of birth including months

4 个答案: