Is there a single character day of the week convention?

Question

Is there a single character convention for the days of the week in English (or programmer-specific) and if so what is it? I realize this could be an English language question but I think it has special significance for programmers.

Maybe something like:

Monday    Mon  MO  M
Tuesday   Tue  TU  T
Wednesday Wed  WE  W
Thursday  Thu  TH  U
Friday    Fri  FR  F
Saturday  Sat  SA  S
Sunday    Sun  SU  N

Anetteaneurin

I've usually seen 'H' for Thursday. – Uncle

ha, I'm used to 'R' for thursday – Composure

I'll stick to a comment, but I am fairly certain the answer is, "No." I am familiar with "S M T W T F S" as single letters standing for each of the days of the week in sequence, but I have never seen a unique single letter encoding, though I am sure any number of people have implemented one. If you need one, just use "1 2 3 4 5 6 7" and take advantage of the much wider use of Arabic numerals as compared to English word abbreviations... – Disagreement

@Disagreement It's a bad idea to use 1~7 because in Chinese Monday through Saturday are literally called 1day through 6day (Sunday is still Sunday). Unless you're fine with putting Sunday at 7 or 0 it would clash there. That said, I have no idea if numbers would clash with other languages. – Inflammable

Answer 1

Perhaps this is an authority? They recommend, M T W R F S U http://eventguide.com/topics/one_digit_day_abbreviations.html

In any case, what's probably most important is that the end-user has documentation telling which arbitrary choice you've decided on.

Uncle

It is kind of odd that they chose "R" as the least ambiguous letter for Thursday when in fact "H" is completely unambiguous – Anetteaneurin

I agree, but I imagine it's based more on phonetics than spelling. I.e. you hear the "ur" part of Thursday but not the H itself. Pure speculation though. – Uncle

Answer 2

Understood that this question is an old one, but for new searchers (like me) who bump into it: The MTWRFSU convention for unambiguous single-letter references to Monday through Sunday appears to be relatively common. I first encountered it at George Washington University in the late 80s, where it was used in the class registration process. Googling "mtwrfsu" shows that it persists in academic IT all over the US, for example: https://sa.ucla.edu/ro/Public/SOC/Results/ClassDetail?term_cd=161&subj_area_cd=WL%20ARTS&crs_catlg_no=0174A%20%20%20&class_id=401744210&class_no=%20002%20%20

FWIW, I've been using it regularly in schedule annotation in English-language business contexts for 30+ years and have very rarely seen anyone not get it, without any explanation required.

Dapper