Read or set the declared encodings for a character vector.
Encoding(x)Encoding(x) <- value
enc2native(x)
enc2utf8(x)
A character vector.
A character vector of positive length.
A character vector.
For enc2utf8 encodings are always marked: they are for
enc2native in UTF-8 and Latin-1 locales.
Character strings in R can be declared to be encoded in
"latin1" or "UTF-8" or as "bytes". These
declarations can be read by Encoding, which will return a
character vector of values "latin1", "UTF-8"
"bytes" or "unknown", or set, when value is
recycled as needed and other values are silently treated as
"unknown". ASCII strings will never be marked with a declared
encoding, since their representation is the same in all supported
encodings. Strings marked as "bytes" are intended to be
non-ASCII strings which should be manipulated as bytes, and never
converted to a character encoding (so writing them to a text file is
not supported).
enc2native and enc2utf8 convert elements of character
vectors to the native encoding or UTF-8 respectively, taking any
marked encoding into account. They are primitive functions,
designed to do minimal copying.
There are other ways for character strings to acquire a declared
encoding apart from explicitly setting it (and these have changed as
R has evolved). Functions scan,
read.table, readLines, and
parse have an encoding argument that is used to
declare encodings, iconv declares encodings from its
to argument, and console input in suitable locales is also
declared. intToUtf8 declares its output as
"UTF-8", and output text connections (see
textConnection) are marked if running in a
suitable locale. Under some circumstances (see its help page)
source(encoding=) will mark encodings of character
strings it outputs.
Most character manipulation functions will set the encoding on output
strings if it was declared on the corresponding input. These include
chartr, strsplit(useBytes = FALSE),
tolower and toupper as well as
sub(useBytes = FALSE) and gsub(useBytes =
FALSE). Note that such functions do not preserve the
encoding, but if they know the input encoding and that the string has
been successfully re-encoded (to the current encoding or UTF-8), they
mark the output.
substr does preserve the encoding, and
chartr, tolower and toupper
preserve UTF-8 encoding on systems with Unicode wide characters. With
their fixed and perl options, strsplit,
sub and gsub will give a marked UTF-8 result if
any of the inputs are UTF-8.
paste and sprintf return elements marked
as bytes if any of the corresponding inputs is marked as bytes, and
otherwise marked as UTF-8 of any of the inputs is marked as UTF-8.
match, pmatch, charmatch,
duplicated and unique all match in UTF-8
if any of the elements are marked as UTF-8.
There is some ambiguity as to what is meant by a ‘Latin-1’ locale, since some OSes (notably Windows) make use of character positions used for control characters in the ISO 8859-1 character set. How such characters are interpreted is system-dependent but as from R 3.5.0 they are if possible interpreted as per Windows codepage 1252 (which Microsoft calls ‘Windows Latin 1 (ANSI)’) when converting to e.g.UTF-8.
# NOT RUN {
## x is intended to be in latin1
x <- "fa\xE7ile"
Encoding(x)
Encoding(x) <- "latin1"
x
xx <- iconv(x, "latin1", "UTF-8")
Encoding(c(x, xx))
c(x, xx)
Encoding(xx) <- "bytes"
xx # will be encoded in hex
cat("xx = ", xx, "\n", sep = "")
# }
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