Time vs DateTime

time-vs-datetime.md

From https://docs.ruby-lang.org/en/2.4.0/DateTime.html#class-DateTime-label-When+should+you+use+DateTime+and+when+should+you+use+Time-3F:

So when should you use DateTime in Ruby and when should you use Time? Almost certainly you'll want to use Time since your app is probably dealing with current dates and times. However, if you need to deal with dates and times in a historical context you'll want to use DateTime to avoid making the same mistakes as UNESCO.

time_vs_datetime_now.rb

require 'benchmark'
require 'date'

Benchmark.bm do |bm|
  bm.report('DateTime:') do
    1_000_000.times { DateTime.now }
  end
  bm.report('Time:    ') do
    1_000_000.times { Time.now }
  end
end

time_vs_datetime_now.sh-session

$ ruby time_vs_datetime.rb
       user     system      total        real
DateTime:  0.820000   0.010000   0.830000 (  0.824737)
Time:      0.410000   0.000000   0.410000 (  0.415594)

time_vs_datetime_parse.rb

require 'time'

p DateTime.now.zone
p Time.now.zone

time = '2016-09-04 11:10:14.495219'

p DateTime.parse(time).zone
p Time.parse(time).zone

time_vs_datetime_parse.sh-session

$ ruby time_vs_datetime_parse.rb
"+10:00"
"AEST"
"+00:00"
"AEST"