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rubydatetime

How do I set date time to 1 month ago with DateTime.now.strftime("%Y-%m-%d")?

I am trying to use set Google Analytics start date and end date to capture unique visitors within the last 30 days. I have made end_date = DateTime.now.strftime("%Y-%m-%d"), how do I set start_date to 30 days ago.

Solution

  • The problem is you're going too far with your creation of end_date.

    You're turning it into a string, which has no math capabilities. Instead, leave it as a DateTime and you inherit the ability to add and subtract integers to do date math:

    require 'date'

datetime_now = DateTime.now
end_date = datetime_now.strftime("%Y-%m-%d") # => "2013-08-06"
end_date.class # => String

end_date = datetime_now # => #<DateTime: 2013-08-06T14:55:20-07:00 ((2456511j,78920s,731393000n),-25200s,2299161j)>
end_date - 30 # => #<DateTime: 2013-07-07T14:55:20-07:00 ((2456481j,78920s,731393000n),-25200s,2299161j)>

    Notice that end_date - 30 returns a DateTime that is exactly 30 days earlier; The time component is preserved. Convert the value to a string once you have the value you want.