get next/previous month from a Time object

Question

I have a Time object and would like to find the next/previous month. Adding subtracting days does not work as the days per month vary.

time = Time.parse('21-12-2008 10:51 UTC') next_month = time + 31 * 24 * 60 * 60 

Incrementing the month also falls down as one would have to take care of the rolling

time = Time.parse('21-12-2008 10:51 UTC') next_month = Time.utc(time.year, time.month+1)  time = Time.parse('01-12-2008 10:51 UTC') previous_month = Time.utc(time.year, time.month-1) 

The only thing I found working was

time = Time.parse('21-12-2008 10:51 UTC') d = Date.new(time.year, time.month, time.day) d >>= 1 next_month = Time.utc(d.year, d.month, d.day, time.hour, time.min, time.sec, time.usec) 

Is there a more elegant way of doing this that I am not seeing? How would you do it?

Answer 1

Ruby on Rails

Note: This only works in Rails (Thanks Steve!) but I'm keeping it here in case others are using Rails and wish to use these more intuitive methods.

Super simple - thank you Ruby on Rails!

Time.now + 1.month  Time.now - 1.month   

Or, another option if it's in relation to the current time (Rails 3+ only).

1.month.from_now  1.month.ago