Date subtraction in Ruby

Question

I have a class that has two params: start_date and end_date .

Those are formatted like - 2012-07-12 and 2012-07-24.

I was to subtract end_date from start_date .

Previous Googling has left me high and dry. Should I convert these to something else to do subtraction?

Answer 1

Convert them into dates and subtract them:

require 'date'

start_date = Date.parse('2012-07-12')
end_date = Date.parse('2012-07-24')

(start_date - end_date).to_i

=> -12

Answer 2

If you want the number of days (end_date-start_date).days should work fine. You'll probably get a Rational number of days, in which case you can just use to_i

Answer 3

If i am not miskaten, the params come in form of a String , so you have to convert it to a Date , DateTime , or Time to do math operations with them.
You can refer to this question to more details.
How can I find the number of days between two Date objects in Ruby?

Answer 4

You can just substract two DateTime objects

Using 1.9

require 'date'
DateTime.parse(end_date) - DateTime.parse(start_date)