Spell date in Japanese

Question

Objective

Given a date, spell it out in Romanized Japanese.

I/O Format

The input format is flexible. The output format is <month spelling> <day spelling>; note the space. You can freely mix cases in output. You may output trailing newline.

Mapping

Months

Month	Spelling
January	Ichigatsu
February	Nigatsu
March	Sangatsu
April	Shigatsu or Yongatsu
May	Gogatsu
June	Rokugatsu
July	Shichigatsu or Nanagatsu
August	Hachigatsu
September	Kugatsu or Kyuugatsu
October	Juugatsu
November	Juuichigatsu
December	Juunigatsu

Days

Irregular ones are marked *.

Day	Spelling
1st	Tsuitachi*
2nd	Futsuka*
3rd	Mikka*
4th	Yokka*
5th	Itsuka*
6th	Muika*
7th	Nanoka*
8th	Youka*
9th	Kokonoka*
10th	Tooka*
11th	Juuichinichi
12th	Juuninichi
13th	Juusannichi
14th	Juuyokka*
15th	Juugonichi
16th	Juurokunichi
17th	Juunananichi
18th	Juuhachinichi
19th	Juukyuunichi
20th	Hatsuka*
21st	Nijuuichinichi
22nd	Nijuuninichi
23rd	Nijuusannichi
24th	Nijuuyokka*
25th	Nijuugonichi
26th	Nijuurokunichi
27th	Nijuunananichi
28th	Nijuuhachinichi
29th	Nijuukyuunichi
30th	Sanjuunichi
31st	Sanjuuichinichi

Examples

• May 5th → Gogatsu Itsuka
• September 29th → Kugatsu Nijuukyuunichi or Kyuugatsu Nijuukyuunichi
• October 9th → Juugatsu Kokonoka

Answer 1

Charcoal, 148 bytes

≔⪪”↶±UH fＸ>¡yüεω!Ln⎇$φＬ¹Kσ⎚FV” ζＮθＦ÷θχjuu§ζθgatsu Ｎη¿››ηχ⁼η²⁰«Ｆ÷η²⁰§ζ÷ηχjuu¿⁼⁴﹪ηχyokka⁺§ζηnichi»«§⪪”↶±‽″÷iπλº⊗wÞαα↓✳C⍘↔ω‖σ?Ｈê⦃¡ＢUQ(Ｕ}⊞▶↔⊙” ﹪η²⁰¿⊖ηka

Try it online! Link is to verbose version of code. Outputs in lower case. Explanation:

≔⪪”...” ζ

Get a list of the base names.

Ｎθ

Input the month number.

Ｆ÷θχjuu

Print "juu" if it is at least 10.

§ζθgatsu 

Output the rest of the month name.

Ｎη

Input the day number.

¿››ηχ⁼η²⁰«

If it's greater than 10 but not 20...

Ｆ÷η²⁰§ζ÷ηχjuu

Output the tens part of the day.

¿⁼⁴﹪ηχyokka

Print "yokka" if the day ends in 4, otherwise...

⁺§ζηnichi

... print the units part of the day.

»«§⪪”...” ﹪η²⁰¿⊖ηka

Otherwise, look up the root day and append "ka" unless the day is 1.

Answer 2

Python 2, 238 bytes

Takes a month \$ m \in [1, 12] \$ and a day \$ d \in [1, 31] \$ as input, and outputs the Romaji in lowercase.

lambda m,d:m/10*'juu'+O[m%10]+'gatsu '+[O[~d%-20]+1%d*'ka',d/20*O[d/10]+'juu'+[O[d%10]+'nichi','yokka'][d%10==4]][20!=d>10]
O=',ichi,ni,san,shi,go,roku,nana,hachi,kyuu,too,kokono,you,nano,mui,itsu,yok,mik,futsu,tsuitachi,hatsu'.split(',')

Try it online!

Answer 3

JavaScript (ES6), 236 bytes

Expects (month)(day) as integers in \$[1,12]\$ and \$[1,31]\$ respectively.

m=>d=>(a="/ichi/ni/san/shi/go/roku/nana/hachi/kyuu/futsu/mik/yok/itsu/mui/nano/you/kokono/too".split`/`,m>9?"juu":"")+a[m%10]+"gatsu "+(d<11?d-1?a[d+8]+"ka":"tsuitachi":d-20?a[d/10^d<20]+"juu"+(d%10-4?a[d%10]+"nichi":"yokka"):"hatsuka")

Try it online!

Commented

m => d =>                  // m = month, d = day
(                          //
  a = (                    // a[] is a lookup array containing:
    "/ichi/ni/.../kyuu/" + //     0-9: regular prefixes for 0 to 9
    "futsu/mik/.../too"    //   10-18: irregular prefixes for 2nd to 10th
  ).split`/`,              //
  m > 9 ? "juu" : ""       // start with "juu" if m > 9
) +                        //
a[m % 10] +                // append the regular prefix for m
"gatsu " +                 // followed by "gatsu "
(                          //
  d < 11 ?                 // if d is less than 11:
    d - 1 ?                //   if d is not equal to 1:
      a[d + 8] +           //     append the irregular prefix for d
      "ka"                 //     followed by "ka"
    :                      //   else (d = 1):
      "tsuitachi"          //     "1st" is "tsuitachi"
  :                        // else (d > 10):
    d - 20 ?               //   if d is not equal to 20:
      a[d / 10 ^ d < 20] + //     according to the tens digit of d,
                           //     append either "" or "ni" or "san"
      "juu" +              //     followed by "juu"
      (                    //     followed by:
        d % 10 - 4 ?       //       if d mod 10 is not 4:
          a[d % 10] +      //         use the regular prefix for d
          "nichi"          //         followed by "nichi"
        :                  //       else:
          "yokka"          //         use the irregular "yokka"
      )                    //
    :                      //   else (d = 20):
      "hatsuka"            //     "20th" is "hatsuka"
)                          //

Answer 4

K (ngn/k), 273 bytes

g:m:$``ICHI`NI`SAN`SHI`GO`ROKU`SHICHI`HACHI`KU
d:($``TSUITACHI),($`FUTSU`MIK`YOK`ITSU`MUI`NANO`YOU`KOKONO`TOU`HATSU),\:$`KA
g:g,\:n:$`NICHI
g[4 7]:d[4 7]
g[7]:(-3_g[7]),"A",n
k:(-1_d),1_,/m[-1 2 3],/:\:"JYUU",/:g
k[20]:*|d
j:(,/($``JYUU),/:\:m;k)
f:"gatsu "/{(*x),_1_x}'j@'

Try it online!

I booted earlier versions. Thanks to @ngn for saving 5 bytes.

Answer 5

///, 293 bytes

/[1-/1@/
/[1/_1/
/[7/sh1/
/[4/shi/
/[9/ku/
/[//
/@/-/
/-/gatsu _/

/_1]/tsuitachi/
/_2]/futsuK/
/_3]/mikK/
/_4]/yokK/
/_5]/itsuK/
/_6]/muiK/
/_7]/nanoK/
/_8]/youK/
/_9]/kokonoK/
/_10]/tooK/
/_20]/hatsuK/

/_1/juu/
/_2/2_1/
/_3/3_1/

/4]/yokK/
/K/ka/
/]/n1/

/0//
/1/ichi/
/2/ni/
/3/san/
/5/go/
/6/roku/
/7/nana/
/8/hachi/
/9/kyuu/

Attempt This Online!

Newlines are added just for clarity and stripped before execution. Input is expected in [M-D] format and is appended at the end of the program since the language does not support any form of input.

Answer 6

Ruby, 255 235 bytes

%W() declares a space-separated array of strings, which is useful for saving bytes over a split solution. An empty string interpolation #{} is needed to make the first element an empty string.

-3 bytes by incorporating dingledooper's array scheme for storing the special day cases.

->m,d{n=%W(#{} ichi ni san yon go roku nana hachi kyuu too kokono you nano mui itsu yok mik futsu tsuitachi hatsu)
'juu'*(m/10)+n[m%10]+"gatsu "+(d==20||d<11?n[~d%-20]+'ka'*(1%d):n[d/10]*(d/20)+'juu'+(d%10==4?'yokka':n[d%10]+'nichi'))}

Attempt This Online!