I found a way to calculate the age in rails. Can some one explain this code?

Question

Sorry Im new to rails. I just found a way to calculate the age in a model from here : Get person's age in Ruby

The function is this :

def age
  now = Time.now.utc
  now.year - birthday.year - (birthday.to_time.change(:year => now.year) > now ? 1 : 0)
end

Can some one please explain whats happening in the third line? I can't understand this :

(birthday.to_time.change(:year => now.year) > now ? 1 : 0)

looking up the ternary operator (like: `cond ? yes : no`) should clear thing up — kostja, Dec 02 '13 at 11:56
Use http://stackoverflow.com/a/2357790/2503775, not the check-marked one which can't handle leap years.. — user2503775, Dec 02 '13 at 12:22

score 2 · Accepted Answer · answered Dec 02 '13 at 12:22

That sentence is only trying to check if the birthday has already passed for the current year. If it has, then

(birthday.to_time.change(:year => now.year) > now ? 1 : 0)

will equal to 0. otherwise 1. this will be then subtracted like this:

now.year - birthday.year - 1 or now.year - birthday.year - 0

Hope that clarifies your doubt.

Just a suggestion, I would rather use irb and break up above code in smaller pieces and see what each part does exactly for myself. This would help me understand stuff better.

I found a way to calculate the age in rails. Can some one explain this code?

1 Answers1