Palindromic date

[Bob Martin]

I told my son that today's date is a palindrome - 20200202 - and asked when it last happened. He reckons it was Dec 31st, 1321 - 13211231. Is he right?

[Richard]

no

[Andy Burns]

No, 29th Nov 1192 in the UK

[The Natural Philosopher]

that is the 12th day of the 31st month

[ARW]

What's wrong with 10th Feb 2001?

Although in the US it would be 2nd Oct 2001

[GB]

It depends on what format you use for the date. For example, 18/9/1981 is palindromic, but 18/09/1981 is not.

[Chris Hogg]

Depends on the format:

Palindrome Days in 2020-2021

mm-dd-yyyy

February 2, 2020 (02-02-2020) December 2, 2021 (12-02-2021)

dd-mm-yyyy

2 February, 2020 (02-02-2020) 12 February, 2021 (12-02-2021)

mm-dd-yy

February 11, 2020 (02-11-20) February 22, 2020 (02-22-20) December 11, 2021 (12-11-21) December 22, 2021 (12-22-21)

m-dd-yyyy

January 20, 2021 (1-20-2021)

Different Digits

In addition to the format, many people around the world also write the digits of the date differently. For instance, it is common to write only the last two digits of the year ? so, 20 instead of 2020. Other date representations include:

d-m-yy or 2-2-20 d-m-yyyy or 2-2-2020 dd-mm-yy or 02-02-20 dd-mm-yyyy or 02-02-2020 mm-dd-yy or 02-02-20 mm-dd-yyyy or 02-02-2020

Each of these date formats has its own Palindrome Days.

[Brian Gaff (Sofa 2)]

The US has the day and date the other way around. I'm not sure its palindrome today in any case. Brian

[Pancho]

It's clearly nowhere as special as pretending it hasn't happened for a thousand years.

Your so dumb! I want to feel special.

I mean what answer do you give when your girlfriend asks "does my bum look big in this"?

[Richard]

His what?

[Dr S Lartius]

No, to the question as given; New Year's Day 2011, commonly written as 1111 when compressed, was palindromic.

Now ask him when the most recent palindromic ordinal date was. No week-numbering dates are palindromic, as such invariably contain a non-central "W".

Consult ISO8601.

[Richard]

No, 11 November 2011 was more recent. 111111

[Bob Martin]

I was assuming ISO date format of YYYYMMDD What format is 11922911? YYYYDDMM? Who uses that?

[NY]

If you assume an 8-digit date DDMMYYYY then the next is 12022021 and the last three have been 21020212, 11022011 and 01022010.

[Dr S Lartius]

I used to think that no-one would be daft enough to use YYYYDDMM, but a Google search showed that I was mistaken. It is, or it was, used by an Agency of the US Government.

[Roger Mills]

Indeed. Today's date is unusual in that it works for either format:

02-02-2020 or 2020-02-02 are both palindromic *and* it matters not whether day is before or after month. It works for dd-mm-yyyy, mm-dd-yyyy, yyyy-mm-dd and yyyy-dd-mm

All the other examples quoted are format-specific.The last time we had one like today would have been on 01-01-1010

[The Natural Philosopher]

21020212 is not palindromic...

[The Other Mike]

I'd hazard a guess at ANSI, and as usual the merkins would claim it as a universal standard to be adopted by all under pain of invasion, sanctions or a nuclear strike.

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