stri_enc_toutf8: Convert Strings To UTF-8#


Converts character strings with declared marked encodings to UTF-8 strings.


stri_enc_toutf8(str, is_unknown_8bit = FALSE, validate = FALSE)



a character vector to be converted


a single logical value, see Details


a single logical value (can be NA), see Details


If is_unknown_8bit is set to FALSE (the default), then R encoding marks are used, see stri_enc_mark. Bytes-marked strings will cause the function to fail.

If a string is in UTF-8 and has a byte order mark (BOM), then the BOM will be silently removed from the output string.

If the default encoding is UTF-8, see stri_enc_get, then strings marked with native are – for efficiency reasons – returned as-is, i.e., with unchanged markings. A similar behavior is observed when calling enc2utf8.

For is_unknown_8bit=TRUE, if a string is declared to be neither in ASCII nor in UTF-8, then all byte codes > 127 are replaced with the Unicode REPLACEMENT CHARACTER (\Ufffd). Note that the REPLACEMENT CHARACTER may be interpreted as Unicode missing value for single characters. Here a bytes-marked string is assumed to use an 8-bit encoding that extends the ASCII map.

What is more, setting validate to TRUE or NA in both cases validates the resulting UTF-8 byte stream. If validate=TRUE, then in case of any incorrect byte sequences, they will be replaced with the REPLACEMENT CHARACTER. This option may be used in a case where you want to fix an invalid UTF-8 byte sequence. For NA, a bogus string will be replaced with a missing value.


Returns a character vector.


Marek Gagolewski and other contributors

See Also#

The official online manual of stringi at

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 encoding_conversion: about_encoding, stri_enc_fromutf32(), stri_enc_toascii(), stri_enc_tonative(), stri_enc_toutf32(), stri_encode()