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Outputting ordinal numbers (1st, 2nd, 3rd)

I would like to generate (as a return result of a function, or simply as the output of a program) the ordinal suffix of a positive integer concatenated to the number.

Samples:

1st 
2nd 
3rd 
4th 
... 
11th 
12th 
13th 
... 
20th 
21st
22nd
23rd
24th

And so on, with the suffix repeating the initial 1-10 subpattern every 10 until 100, where the pattern ultimately starts over.

The input would be the number and the output the ordinal string as shown above.

What is the smallest algorithm for this?

Answer*

# [APL (Dyalog Unicode)], <s>38</s> 36 bytes

Thanks to ngn for fixing a bug while maintaining byte count.



Anonymous tacit prefix function. Requires `⎕IO` (**I**ndex **O**rigin) set to `0`, which is default on many systems. Even works for 0!

 ⍕,{2↑'thstndrd'↓⍨2×⊃⍵⌽∊1 0 8\⊂10↑⍳4}

[Try it online!][TIO-jgqvii2e]

[APL (Dyalog Unicode)]: https://www.dyalog.com/
[TIO-jgqvii2e]: https://tio.run/##SyzI0U2pTMzJT///qG9qZv6jtgkG/9OA5KPeqTrVRo/aJqqXZBSX5KUUpag/apv8qHeF0eHpj7qaH/VufdSz91FHl6GCgYJFzKOuJkMDoOJHvZtNav//T1Mw4EpTMARiIwUFIGkMJk2ApLqenp46SM4QLGQIkTc0RpIyMgCLGYG1G4EIYxBhAgA "APL (Dyalog Unicode) – Try It Online"

`{`…`}` anonymous lambda; `⍵` is argument:

 `⍳4` first four **ɩ**ndices; `[0,1,2,3]`

 `10↑` take first ten elements from that, padding with zeros: `[0,1,2,3,0,0,0,0,0,0]`

 `⊂` enclose to treat as single element; `[[0,1,2,3,0,0,0,0,0,0]]`

 `1 0 8\` expand to one copy, a prototypical copy (all-zero), eight copies; 
  <code>[[0,1,2,3,0,0,0,0,0,0],</code> 
  <code> [0,0,0,0,0,0,0,0,0,0],</code> 
  <code> [0,1,2,3,0,0,0,0,0,0],</code> 
  <code> [0,1,2,3,0,0,0,0,0,0],</code> 
   ⋮ (5 more) 
  <code> [0,1,2,3,0,0,0,0,0,0]]</code> 

 `∊` **ϵ**nlist (flatten); 
  <code>[0,1,2,3,0,0,0,0,0,0,</code> 
  <code> 0,0,0,0,0,0,0,0,0,0,</code> 
  <code> 0,1,2,3,0,0,0,0,0,0,</code> 
  <code> 0,1,2,3,0,0,0,0,0,0,</code> 
   ⋮ (50 more) 
  <code> 0,1,2,3,0,0,0,0,0,0]</code>

 `⍵⌽` cyclically rotate left as many steps as indicated by the argument

 `⊃` pick the first number (i.e. the argument-mod-100'th number)

 `2×` multiply two by that (gives `0`, `2`, `4`, or `6`)

 `'thstndrd'↓⍨`drop that many characters from this string

 `2↑` take the first two of the remaining characters

`⍕,` concatenate the stringified argument to that

If this is an answer to a challenge…

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…Include a short header which indicates the language(s) of your code and its score, as defined by the challenge.

More generally…

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\$\begingroup\$ "31th"? \$\endgroup\$

ngn
– ngn

2018年05月03日 17:49:53 +00:00
Commented May 3, 2018 at 17:49
\$\begingroup\$ ⍕,{2↑'thstndrd'↓⍨2×⊃⍵⌽∊1 0 8\⊂10↑⍳4} \$\endgroup\$

ngn
– ngn

2018年05月03日 18:23:04 +00:00
Commented May 3, 2018 at 18:23
\$\begingroup\$ sorry, I forgot to mention ⎕io←0. I can see you guessed that, but there are a few 1,2,3,4,0,0... that should be 0,1,2,3,0,0... \$\endgroup\$

ngn
– ngn

2018年05月03日 19:35:21 +00:00
Commented May 3, 2018 at 19:35
\$\begingroup\$ @ngn Fixed. And happens to work for 0 too! \$\endgroup\$

Adám
– Adám

2018年05月03日 20:26:17 +00:00
Commented May 3, 2018 at 20:26

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