How do i get the oldest date from a selection?

Question

I have a selection of dates:

2015-09-25T11:08:00
2015-09-25T11:42:00
2015-09-25T17:02:00
2015-09-25T17:02:00
2015-09-28T13:09:00

How would i get the most recent date from this selection. I was trying to use

@messagedaterows.max {|obj| @message_thread_ID }

Answer 1

2.0.0p353 :005 > test
 => [2015-09-28 17:36:51 +0200, 2015-09-27 17:36:51 +0200] 
2.0.0p353 :006 > test.sort
 => [2015-09-27 17:36:51 +0200, 2015-09-28 17:36:51 +0200] 
2.0.0p353 :007 > test.sort.first
 => 2015-09-27 17:36:51 +0200 
2.0.0p353 :008 > test.sort.last
 => 2015-09-28 17:36:51 +0200 

Answer 2

You don't need complex logic for this.

Simply:

dates.max # => 2015-09-28 13:09:00

Even if they are strings this should work:

dates.max # => "2015-09-28T13:09:00"

Answer 3

The oldest date is also the minimal date . Therefore I would write something like this:

dates = options['Messages'].map { |entry| entry["Date"] }
dates.min
#=> 2015-09-25T11:08:00