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