trimws
Remove Leading/Trailing Whitespace
Remove leading and/or trailing whitespace from character strings.
- Keywords
- character
Usage
trimws(x, which = c("both", "left", "right"), whitespace = "[ \t\r\n]")Arguments
- x
a character vector
- which
a character string specifying whether to remove both leading and trailing whitespace (default), or only leading (
"left") or trailing ("right"). Can be abbreviated.- whitespace
a string specifying a regular expression to match (one character of) “white space”, see Details for alternatives to the default.
Details
Internally, sub(re, "", *, perl = TRUE), i.e., PCRE
library regular expressions are used.
For portability, the default ‘whitespace’ is the character class
[ \t\r\n] (space, horizontal tab, carriage return,
newline). Alternatively, [\h\v] is a good (PCRE)
generalization to match all Unicode horizontal and vertical white
space characters, see also https://www.pcre.org.
Examples
library(base)
# NOT RUN {
x <- " Some text. "
x
trimws(x)
trimws(x, "l")
trimws(x, "r")
## Unicode --> need "stronger" 'whitespace' to match all :
tt <- "text with unicode 'non breakable space'."
xu <- paste(" \t\v", tt, "\u00a0 \n\r")
(tu <- trimws(xu, whitespace = "[\\h\\v]"))
stopifnot(identical(tu, tt))
# }