I recently found out [1] that the Unicode sequences for flag emoji are created by taking the two-letter country abbreviation (ISO 3166-1 alpha-2) and replacing both letters with their counterparts in the range U+1F1E6 through U+1F1FF.

For example, the abbreviation for Canada is CA, and the characters 🇨 (U+1F1e8) and 🇦 (U+1F!E6) together create 🇨🇦.

This is illustrated by the following Python code.

    import iso3166

    def flag_emoji(name):
        alpha = iso3166.countries.get(name).alpha2
        box = lambda ch: chr( ord(ch) + 0x1f1a5 )
        return box(alpha[0]) + box(alpha[1])
    print(flag_emoji("Canada"))

The name we give to flag_emoji need not be the full country name, like Canada. It can be anything that iso3166.countries.get supports, which also includes two-letter abbreviations like CA, three-letter abbreviations like CAN, or ISO 3166 numeric codes like 124.

We can use the following code to print a collage of flags:

    def print_all_flags():
        for i, c in enumerate( iso3166.countries ):
            print(flag_emoji(c.name), end="")
            if i%25 == 24: print()

Related posts

• Preventing unwanted emoji
• Finding similar flags with Mathematica
• Two-letter and three-letter country abbreviations

[1] I learned this from watching Dylan Beattie’s talk Plain Text on YouTube.

I figured out something that I wasn’t able to find by searching, so I’m posting it here in case other people have the same question and the same difficulty finding an answer.

I’m sure other people have written about this, but I couldn’t find it. Maybe lots of people have written about this in Japanese but not many in English.

Japanese kana consists of two syllabaries, hiragana and katakana, that are like phonetic alphabets. Each has 46 basic characters, and each corresponds to a block of 96 Unicode characters. I had two simple questions:

1. How do the 46 characters map into the 90 characters?
2. Do they map the same way for both hiragana and katakana?

Hiragana / katakana correspondence

I’ll start with the second question because it’s easier. Hiragana and katakana are different ways of representing the same sounds, and they correspond one to one. For example, the full name of U+3047 (ぇ) is

HIRAGANA LETTER SMALL E

and the full name of its katakana counterpart U+30A7 (ェ) is

KATAKANA LETTER SMALL E

The only difference as far as Unicode goes is that katakana has three code points whose hiragana counterpart is unused, but these are not part of the basic letters.

The following Python code shows that the names of all the characters are the same except for the name of the system.

    from unicodedata import name

    unused = [0, 151, 152] # not in hiragana

    for i in range(0,63):
        if i in unused:
            continue
        h = name(chr(0x3040 + i)) 
        k = name(chr(0x30a0 + i))
        assert(h == k.replace("KATAKANA", "HIRAGANA"))
    print("done")

Mapping 46 into 50 and 96

You’ll see kana written in grid with one side labeled with 5 vowels and the other labeled with 10 consonants called a gojūon (五十音). That’s 50 cells, and in fact gojūon literally means 50 sounds, so how do we get 46? Five cells are empty, and one letter doesn’t fit into the grid. The empty cells are unused or archaic, and the extra character doesn’t fit the grid structure.

In the image below, the table on the left is for hiragana and the table on the right is for katakana. HTML versions of the tables available here.

Left out of each table is ん in hiragana and ン in katakana.

So does each set of 46 characters map into its Unicode code block?

Unicode numbers the letters consecutively if you traverse the grid increasing vowels first, then consonants, and adding the straggler at the end. But the reason 46 letters expand into more code points is that each letter can have one, two, or three variations. And there are various miscellaneous other symbols in the Unicode block.

For example, there is a LETTER E as well as the SMALL LETTER E mentioned above. Other variations seem to correspond to voiced and unvoiced versions of a consonant with a phonetic marker added to the voiced version. For example, く is U+304F, HIRAGANA LETTER KU, and ぐ is U+3050, HIRAGANA LETTER GU.

Here is how hiragana maps into Unicode. Each cell should be U+3000 plus the characters show.

         a  i  u  e  o 
        42 44 46 48 4A 
     k  4B 4D 4F 51 53 
     s  55 57 59 5B 5D 
     t  5F 61 64 66 68 
     n  6A 6B 6C 6D 6E 
     h  6F 72 75 78 7B 
     m  7E 7F 80 81 82 
     y  84    86    88 
     r  89 8A 8B 8C 8D 
     w  8F          92 

The corresponding table for katakana is the previous table plus 0x60:

         a  i  u  e  o 
        A2 A4 A6 A8 AA 
     k  AB AD AF B1 B3 
     s  B5 B7 B9 BB BD 
     t  BF C1 C4 C6 C8 
     n  CA CB CC CD CE 
     h  CF D2 D5 D8 DB 
     m  DE DF E0 E1 E2 
     y  E4    E6    E8 
     r  E9 EA EB EC ED 
     w  EF          F2 

In each case, the letter missing from the table is the next consecutive value after the last in the table, i.e. ン is U+30F3.

Related posts

• Graphing Japanese prefectures
• Alphabets in Unicode

I was spelunking around in Unicode and found that there are assigned characters for representing domino tiles and that the characters are enumerated in a convenient order. Here is the code chart.

There are codes for representing tiles horizontally or vertically. And even though, for example, the 5-3 is the same domino as the 3-5, there are separate characters for representing the orientation of the tile: one for 3 on the left and one for 5 on the left.

When you include orientation like this, a domino becomes essentially a base 7 number: the number of spots on one end is the number of 7s and the number of spots on the other end is the number of 1s. And the order of the characters corresponds to the order as base 7 numbers:

0-0, 0-1, 0-2, …, 1-0, 1-1, 1-2, … 6-6.

The horizontal dominoes start with the double blank at U+1F031 and the vertical dominoes start with U+1F063, a difference of 32 in hexadecimal or 50 in base 10. So you can rotate a domino tile by adding or subtracting 50 to its code point.

The following tiny Python function gives the codepoint for the domino with a spots on the left (or top) and b spots on the right (or bottom).

    def code(a, b, wide):
        cp = 0x1f031 if wide else 0x1f063
        return cp + 7*a + b

We can use this function to print a (3, 5) tile horizontally and a (6, 4) tile vertically.

    print( chr(code(3, 5, True )),
           chr(code(6, 4, False)) )

To my surprise, my computer had the fonts installed to display the results. This isn’t guaranteed for such high Unicode values.