Convert between hiragana and katakana

to_hiragana() maps katakana to hiragana and to_katakana() maps the other way. Kanji, Latin text and punctuation are untouched.

Usage

to_hiragana(x)

to_katakana(x)

Arguments

x

A character vector. Anything else is coerced with as.character(). That coercion is R's, not this package's, so a numeric vector is measured as R chooses to write it – which moves with options(scipen) and options(OutDec), and can therefore differ between sessions. Convert deliberately if you mean to measure numbers; these verbs are for text. A list is not coerced – as.character() deparses one rather than coercing it, so the text measured would be the R code that builds the list – so a list, a data frame or a function is an error naming what to do instead.

Value

A character vector the same length as x. NA gives NA.

Details

The two kana syllabaries encode the same sounds, so this conversion is unambiguous – unlike cjk_romanize() or cjk_simplify(), there is no context that could change the answer. It is the normalisation you want before comparing or grouping Japanese text, where the same word may be written either way for emphasis.

It is a normalisation, not a reversible mapping. Applied to text holding both syllabaries it erases the distinction between them, and that distinction means something: katakana marks loanwords, onomatopoeia and emphasis. to_katakana(to_hiragana(x)) turns any hiragana in x into katakana, and it is not exact even on text that was all katakana, because ICU's mapping makes a few choices of its own: the small katakana U+30F5 and U+30F6 become the full-size hiragana U+304B and U+3051, and the digraphs U+30FF (koto) and U+309F (yori) are spelled out as two kana each. Run it one way, and keep the original if you need to go back.

Halfwidth katakana is handled too, and composed while it is: the halfwidth voiced KA is two code points, U+FF76 and U+FF9E, and to_katakana() returns the single character U+30AC. So no width conversion is needed first, though to_halfwidth() and to_fullwidth() remain the way to move along the width axis without touching the syllabary.

See also

to_halfwidth() for the width axis, cjk_script() to see which kana a string is in.

Examples

to_hiragana("\u30ab\u30bf\u30ab\u30ca")   # katakana -> hiragana
#> [1] "かたかな"
to_katakana("\u3072\u3089\u304c\u306a")   # and back
#> [1] "ヒラガナ"

# kanji is left alone
to_katakana("\u65e5\u672c\u8a9e\u3067\u3059")
#> [1] "日本語デス"