R: Character Translation and Casefolding

chartr {base} | R Documentation

## Character Translation and Casefolding

### Description

Translate characters in character vectors, in particular from upper to lower case or vice versa.

### Usage

    chartr(old, new, x)
    tolower(x)
    toupper(x)
    casefold(x, upper = FALSE)

### Arguments

`x` | a character vector.
`old` | a character string specifying the characters to be translated.
`new` | a character string specifying the translations.
`upper` | logical: translate to upper or lower case?.

### Details

`chartr` translates each character in `x` that is specified in `old` to the corresponding character specified in `new`. Ranges are supported in the specifications, but character classes and repreated characters are not. If `old` contains more characters than new, an error is signaled; if it contains fewer characters, the extra characters at the end of `new` are ignored.

`tolower` and `toupper` convert upper-case characters in a character vector to lower-case, or vice versa. Non-alphabetic characters are left unchanged.

`casefold` is a wrapper for `tolower` and `toupper` provided for compatibility with S-PLUS.

### See Also

`sub` and `gsub` for other substitutions in strings.

### Examples

    x <- "MiXeD cAsE 123"
    chartr("iXs", "why", x)
    chartr("a-cX", "D-Fw", x)
    tolower(x)
    toupper(x)

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