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Ruby - DateTime
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  DateTime from string

DateTime.parse is a very useful method which construct a DateTime from a string, guessing its format.

DateTime.parse('Jun, 8 2016')
# => #<DateTime: 2016-06-08T00:00:00+00:00 ((2457548j,0s,0n),+0s,2299161j)>
DateTime.parse('201603082330')
# => #<DateTime: 2016-03-08T23:30:00+00:00 ((2457456j,84600s,0n),+0s,2299161j)>
DateTime.parse('04-11-2016 03:50')
# => #<DateTime: 2016-11-04T03:50:00+00:00 ((2457697j,13800s,0n),+0s,2299161j)>
DateTime.parse('04-11-2016 03:50 -0300')
# => #<DateTime: 2016-11-04T03:50:00-03:00 ((2457697j,24600s,0n),-10800s,2299161j)

Note: There are lots of other formats that parse recognizes.
  New 
DateTime.new(2014,10,14)
# => #<DateTime: 2014-10-14T00:00:00+00:00 ((2456945j,0s,0n),+0s,2299161j)>

Current time:

DateTime.now
# => #<DateTime: 2016-08-04T00:43:58-03:00 ((2457605j,13438s,667386397n),-10800s,2299161j)>

Note that it gives the current time in your timezone
  Add/substract days to DateTime

DateTime + Fixnum (days quantity)

DateTime.new(2015,12,30,23,0) + 1
# => #<DateTime: 2015-12-31T23:00:00+00:00 ((2457388j,82800s,0n),+0s,2299161j)>

DateTime + Float (days quantity)

DateTime.new(2015,12,30,23,0) + 2.5
# => #<DateTime: 2016-01-02T11:00:00+00:00 ((2457390j,39600s,0n),+0s,2299161j)>

DateTime + Rational (days quantity)

DateTime.new(2015,12,30,23,0) + Rational(1,2)
# => #<DateTime: 2015-12-31T11:00:00+00:00 ((2457388j,39600s,0n),+0s,2299161j)>

DateTime - Fixnum (days quantity)

DateTime.new(2015,12,30,23,0) - 1
# => #<DateTime: 2015-12-29T23:00:00+00:00 ((2457388j,82800s,0n),+0s,2299161j)>

DateTime - Float (days quantity)

DateTime.new(2015,12,30,23,0) - 2.5
# => #<DateTime: 2015-12-28T11:00:00+00:00 ((2457385j,39600s,0n),+0s,2299161j)>

DateTime - Rational (days quantity)

DateTime.new(2015,12,30,23,0) - Rational(1,2)
# => #<DateTime: 2015-12-30T11:00:00+00:00 ((2457387j,39600s,0n),+0s,2299161j)>

Syntax

  • DateTime.new(year, month, day, hour, minute, second)

Remarks

Before using DateTime you need to require 'date'

 

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https://develop.horje.com/learn/1434/reference

 

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