R: Read or Set the Declared Encodings for a Character Vector

Encoding {base} | R Documentation

## Read or Set the Declared Encodings for a Character Vector

### Description

Read or set the declared encodings for a character vector.

### Usage

    Encoding(x)

    Encoding(x) <- value

    enc2native(x)
    enc2utf8(x)

### Arguments

`x` | A character vector.
`value` | A character vector of positive length.

### Details

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.

`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.

### Value

A character vector.

For `enc2utf8` encodings are always marked: they are for `enc2native` in UTF-8 and Latin-1 locales.

### Examples

    ## 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 = "")

[Package base version 3.1.2 Index]