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Unlike specifying the encoding argument in as_string() and as_character(), which is only declarative, these functions actually attempt to convert the encoding of their input. There are two possible cases:

  • The string is tagged as UTF-8 or latin1, the only two encodings for which R has specific support. In this case, converting to the same encoding is a no-op, and converting to native always works as expected, as long as the native encoding, the one specified by the LC_CTYPE locale has support for all characters occurring in the strings. Unrepresentable characters are serialised as unicode points: "<U+xxxx>".

  • The string is not tagged. R assumes that it is encoded in the native encoding. Conversion to native is a no-op, and conversion to UTF-8 should work as long as the string is actually encoded in the locale codeset.

When translating to UTF-8, the strings are parsed for serialised unicode points (e.g. strings looking like "U+xxxx") with chr_unserialise_unicode(). This helps to alleviate the effects of character-to-symbol-to-character roundtrips on systems with non-UTF-8 native encoding.





An object to coerce.


# Let's create a string marked as UTF-8 (which is guaranteed by the
# Unicode escaping in the string):
utf8 <- "caf\uE9"
#> [1] "UTF-8"
#> [1] 63 61 66 c3 a9