How to get the day of year in ruby?

Question

What is the best way to get the day of the year for any specific date in Ruby?

For example: 31/dec/2009 should return day 365, and 01/feb/2008 should return day 32

score 71 · Accepted Answer · edited Sep 22 '15 at 08:09

71

Basically (shown here in irb):

>> require 'date'

>> Date.today.to_s
=> "2009-11-19"

>> Date.today.yday()
=> 323

For any date:

>> Date.new(y=2009,m=12,d=31).yday
=> 365

Or:

>> Date.new(2012,12,31).yday
=> 366

@see also: Ruby Documentation

edited Sep 22 '15 at 08:09

SingerOfTheFall

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answered Nov 19 '09 at 15:14

miku

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1

Cool that you show that yday is not great for comparison across leap years after February :) – toxaq Mar 18 '15 at 10:48

score 3 · Answer 2 · answered Nov 19 '09 at 15:18

3

Use Date.new(year, month, day) to create a Date object for the date you need, then get the day of the year with yday:

>> require 'date'
=> true
>> Date.new(2009,12,31).yday
=> 365
>> Date.new(2009,2,1).yday
=> 32

answered Nov 19 '09 at 15:18

Pär Wieslander

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Jörg W Mittag · Answer 3 · 2009-11-19T15:31:19.550

1

Date#yday is what you are looking for.

Here's an example:

require 'date'

require 'test/unit'
class TestDateYday < Test::Unit::TestCase
  def test_that_december_31st_of_2009_is_the_365th_day_of_the_year
    assert_equal 365, Date.civil(2009, 12, 31).yday
  end
  def test_that_february_1st_of_2008_is_the_32nd_day_of_the_year
    assert_equal 32, Date.civil(2008, 2, 1).yday
  end
  def test_that_march_1st_of_2008_is_the_61st_day_of_the_year
    assert_equal 61, Date.civil(2008, 3, 1).yday
  end
end

edited Nov 19 '09 at 15:31

answered Nov 19 '09 at 15:19

Jörg W Mittag

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I like the use of tests as examples +1 – Toby Apr 16 '15 at 14:27

score 1 · Answer 4 · answered May 02 '18 at 15:04

1

You can use time without importing anything:

Time.new(1989,11,30).yday

or for now:

Time.now.yday

answered May 02 '18 at 15:04

bonafernando

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This should be the best main answer. – Marcos Oct 02 '19 at 18:54

score 0 · Answer 5 · edited Apr 05 '23 at 15:47

0

You might be able to do something with civil_to_jd(y, m, d, sg=GREGORIAN)

edited Apr 05 '23 at 15:47

Cadoiz

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answered Nov 19 '09 at 15:12

John Boker

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How to get the day of year in ruby?

5 Answers5