Editing 1179: ISO 8601

{{comic
| number    = 1179
| date      = February 27, 2013
| title     = ISO 8601
| image     = iso_8601.png
| titletext = ISO 8601 was published on 06/05/88 and most recently amended on 12/01/04.
}}

==Explanation==
When abbreviating the date into numerical form, {{w|Date format by country|various areas of the world}} tend to list the year, month, and day in different orders (as well as with different delimiting symbols), which can cause confusion particularly when the day value is 12 or lower allowing it to be easily interpreted as the month and vice versa. As a public service announcement (https://www.businessstudynotes.com/marketing/marketing-management/purpose-structure-public-service-advertisement-psa/), this comic states that there is in fact one international standard for writing numeric dates, set by the {{w|International Organization for Standardization}} in its {{w|ISO 8601}} standard: YYYY-MM-DD.

The comic then proceeds to list several discouraged ways of writing out the date of the comic's publication, as they do not match the standard. It begins with several commonly used ones in countries around the world, but then begins to list increasingly uncommon ways, ranging from strange (Roman numerals) to quirky (binary, Unix time) to essentially impossible (painting the numbers onto a black cat).

The title text provides a perfect example of the kind of ambiguity that can arise when non-standard formats are used. The ISO standard was in fact published on 1988-06-05 and amended on 2004-12-01. This is mentioned in the title text in MM/DD/YY format; however, there is no way to naturally figure this out, particularly with the second date. With the year truncated to two digits and all three numbers at 12 or lower, the date referring to December 1, 2004 may well be interpreted as 12 January 2004, or as 2012-01-04.

Date formats were again the subject in [[1340: Unique Date]].

The other mentioned formats are:

{| class=wikitable
! Date !! Explanation
|-
| 02/27/2013
| MM/DD/YYYY, used mostly in the United States.
|-
| 02/27/13
| MM/DD/YY, same as above but with the year shortened to two digits.
|-
| 27/02/2013
| DD/MM/YYYY, used variously in South America, Canada ({{w|Date_and_time_notation_in_Canada|officially uses ISO 8601}}), Australia, New Zealand and much of Europe.
|-
| 27/02/13
| DD/MM/YY, same as above but with the year shortened to two digits.
|-
| 20130227
| YYYYMMDD, same as ISO 8601 without delimiting punctuation. Allowed by the standard. Technically not ambiguous but is hard to read as a date at first glance.
|-
| 2013.02.27
| YYYY.MM.DD, used in Japan, South Korea and Hungary. Same as ISO 8601 except with different punctuation.
|-
| 27.02.13
| DD.MM.YY, used in Germany, Russia, and others.
|-
| 27-02-13
| DD-MM-YY, used in Denmark, Netherlands, Indonesia, India, Bangladesh, and others.
|-
| 27.2.13
| D.M.YY. It is common in several areas to abbreviate the month or day to a single digit and drop the leading zero when possible.
|-
| 2013. II. 27.
| YYYY. MM. DD., with month as {{w|Roman numerals}}, used in Hungary.
|-
| <sup>27</sup>⁄<sub>2</sub>-13
| <sup>D</sup>⁄<sub>M</sub>-YY, traditional format in Denmark, Norway and Sweden
|-
| 2013.158904109
| Year and decimal fraction of year. 0.158904109 is a decimal approximation of 58/365, with February 27 being the 58th day of the year. This format may be easier to read for computers/programs in some contexts, but is difficult for humans to interpret.
|-
| MMXIII-II-XXVII
| The ISO 8601 standard but written in Roman numerals. Never used as a traditional standard anywhere as it is hard to read, parse, and interpret for no benefit.
|-
| MMXIII <sup>LVII</sup>⁄<sub>CCCLXV</sub>
| Year followed by its partial fraction 57/365, all in Roman numerals. Equally useless as the above. As a note, apparently this 'standard' is different from the decimal fraction two rows above, as the decimal fraction notation uses the ''end'' of the day (first day of the year is 1/365 while the last is 365/365), while this uses the ''beginning'' (first day is 0/365 and last is 364/365).
|-
| 1330300800
| {{w|Unix time|UNIX Timestamp}}, a standard method of storing absolute time in many computer systems and defined as the number of seconds since 00:00:00 on 1970-01-01 (UTC). The Unix time listed here appears to mistakenly be for '''2012'''-02-27, which is also mentioned by [[Randall]] in the original transcript. The Unix Timestamp for 2013-02-27 would be 1361923200.
|-
| ((3+3)×(111+1)-1)×3/3-1/3<sup>3</sup>
| A useless format where the numbers 2013, 2, and 27 written as needlessly long arithmetic expressions using just the digits 1 and 3. For additional confusion, the values are delimited by slashes, enabling confusion with the fraction bar.  (If evaluated literally, the entire expression evaluates to 670.963, or 671 minus 1 divided by 27.)
|-
| <span style="position:absolute;">&nbsp;&nbsp;&nbsp;2</span><span style="position:absolute;">&nbsp;&nbsp;27</span>2013
| A nearly impossible to read date "format" that can be considered a parody "compromise" between different formats: rather than argue about the order in which the year, month, and day should be, they are simply all written on top of each other. As a "bonus", there is also no arguing over which separator character to use.
|-
| 10/11011/1101
| The US mm/dd/yy format in {{w|Binary number|binary}}, corresponding to 2/27/13. Never used for obvious reasons.
|-
| 02/27/20/13
| MM/DD/CC/YY, where CC stands for century. This format is never used.{{Citation needed}} Note that while months and days count starting from 1, centuries and years in this format count from 0 for extra confusion. But the CC value is widely used on many operating systems to distinguish between the 20th and 21st century, represented by the values "19" and "20" because 1950 belongs to the 20th century.
|-
| <ruby><rb>0</rb><rb>1</rb><rb>2</rb><rb>3</rb><rb>7</rb><rt>2</rt><rt>3</rt><rt>1</rt><rt>4</rt><rtc style="ruby-position: under"><rt>5</rt><rt></rt><rt>67</rt><rt></rt><rt>8</rt></rtc></ruby>
| An obfuscated format where the small numbers indicate the positions where the large digits should be placed. In this reading, 0 is used at positions 2 and 5, 1 is used on position 3, etc.; the result being 20130227
|-
| [A hissing black cat with "2-27-13" painted on it]
| In Western cultures, black cats and the number 13 are associated with bad luck. The cat might also just be angry that someone covered it in paint.
|}

==Transcript==
:Public Service Announcement:

:Our different ways of writing dates as numbers can lead to online confusion. That's why in 1988 ISO set a global standard numeric date format. This is '''''the''''' correct way to write numeric dates:

::2013-02-27

:The following formats are therefore discouraged:
:*02/27/2013
:*02/27/13
:*27/02/2013
:*27/02/13
:*20130227
:*2013.02.27
:*27.02.13
:*27-02-13
:*27.2.13
:*2013. II. 27.
:*<sup>27</sup>⁄<sub>2</sub>-13
:*2013.158904109
:*MMXIII-II-XXVII
:*MMXIII <sup>LVII</sup>⁄<sub>CCCLXV</sub>
:*1330300800
:*((3+3)×(111+1)-1)×3/3-1/3<sup>3</sup>
:*<span style="position:absolute;">&nbsp;&nbsp;&nbsp;2</span><span style="position:absolute;">&nbsp;&nbsp;27</span>2013 [the numbers 2013, 02, and 27 written overlapping each other]
:*10/11011/1101
:*02/27/20/13
:*<sup><sup>2</sup></sup>0<sub><sub>5</sub></sub><sup><sup>3</sup></sup>1<sup><sup>1</sup></sup>2<sub><sub>67</sub></sub><sup><sup>4</sup></sup>37<sub><sub>8</sub></sub>
:*[A black cat with 2-27-13 scrawled across its body in dripping white paint.]
:**Cat: ''Hissss''

{{comic discussion}}
[[Category:Math]]