I'm not sure I would agree with that. ISO-8601 is ambiguous, and very difficult to parse. For example, here are a couple valid ISO-8601 strings. Could you let me know what they mean?

P1DT1H
R10/2021-208/P1Y
T22.3+0800
22,3
2021-W30-2
2021-W30-2T22+08
P1Y
20

Taken from here. My favorite is the last one (20). If someone just wrote 20 and told you to parse it using ISO-8601, what would you get? Hour? It could even be century (ie. 2023%100)!!

So I would argue that ISO-8601 is just a wee bit too flexible. Personally, I like RFC 3339 just a bit more...

Edit: that said, I would definitely agree that something along the lines of 2021-07-27T14:20:32Z is better than any regularly accepted alternative, and I pretty much format my dates that way all the time.

[–] [email protected] 2 points 11 months ago

to be fair, you don't parse "20" without first passing "%C"

[–] [email protected] 1 points 11 months ago* (last edited 11 months ago)

A period of one day and one hour.
A period of one year, ten times, from the 208th day of 2021.
Ten hours and 18 minutes pm (I'm not sure about this one) on UTC+08:00 (China, for example).
IDK.
The 2nd day of the 30th week of 2021.
Same as above, but at 22:00 in China, probably.
A period of one year.
IDK.

[–] [email protected] 0 points 11 months ago (2 children)

Don’t think my bank will like it if I date forms with that.

[–] [email protected] 12 points 11 months ago

Mine doesn't care. It actually never occurred to me not to.

[–] [email protected] 4 points 11 months ago

Yes, and it is used only with dashes instead of slashes. This is also how date is written when you want alphabetical sorting to work on the date, too

[–] Crimsonknee 0 points 11 months ago

Not necessarily. Size of time unit doesn't explicitly mean largest to smallest. For human comprehension day first makes sense because that's the most significant piece of data usually. Likewise for time of day the hour is the most significant piece of data.

Though for computer comprehension, absolutely yyyy/mm/dd is best hands down.