stri_width: Determine the Width of Code Points
Description
Approximates the number of text columns the ‘cat()’ function might use to print a string using a mono-spaced font.
Usage
stri_width(str)
Arguments
|
character vector or an object coercible to |
Details
The Unicode standard does not formalize the notion of a character width. Roughly based on http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c, https://github.com/nodejs/node/blob/master/src/node_i18n.cc, and UAX #11 we proceed as follows. The following code points are of width 0:
code points with general category (see stringi-search-charclass)
Me,Mn, andCf),C0andC1control codes (general categoryCc) - for compatibility with thencharfunction,Hangul Jamo medial vowels and final consonants (code points with enumerable property
UCHAR_HANGUL_SYLLABLE_TYPEequal toU_HST_VOWEL_JAMOorU_HST_TRAILING_JAMO; note that applying the NFC normalization withstri_trans_nfcis encouraged),ZERO WIDTH SPACE (U+200B),
Characters with the UCHAR_EAST_ASIAN_WIDTH enumerable property equal to U_EA_FULLWIDTH or U_EA_WIDE are of width 2.
Most emojis and characters with general category So (other symbols) are of width 2.
SOFT HYPHEN (U+00AD) (for compatibility with nchar) as well as any other characters have width 1.
Value
Returns an integer vector of the same length as str.
References
East Asian Width – Unicode Standard Annex #11, https://www.unicode.org/reports/tr11/
See Also
The official online manual of stringi at https://stringi.gagolewski.com/
Gagolewski M., stringi: Fast and portable character string processing in R, Journal of Statistical Software 103(2), 2022, 1-59, doi:10.18637/jss.v103.i02
Other length: %s$%(), stri_isempty(), stri_length(), stri_numbytes(), stri_pad_both(), stri_sprintf()
Examples
stri_width(LETTERS[1:5])
## [1] 1 1 1 1 1
stri_width(stri_trans_nfkd('\u0105'))
## [1] 1
stri_width(stri_trans_nfkd('\U0001F606'))
## [1] 2
stri_width( # Full-width equivalents of ASCII characters:
stri_enc_fromutf32(as.list(c(0x3000, 0xFF01:0xFF5E)))
)
## [1] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
## [39] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
## [77] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
stri_width(stri_trans_nfkd('\ubc1f')) # includes Hangul Jamo medial vowels and final consonants
## [1] 2