stri_trim_both: Trim Characters from the Left and/or Right Side of a String

Description

These functions may be used e.g. to get rid of unnecessary whitespaces from strings. Trimming ends at the first or starts at the last pattern match.

Usage

stri_trim_both(str, pattern = "\P{Wspace}")
stri_trim_left(str, pattern = "\P{Wspace}")
stri_trim_right(str, pattern = "\P{Wspace}")
stri_trim(str, side = c("both", "left", "right"), pattern = "\P{Wspace}")

Arguments

str

a character vector of strings to be trimmed

pattern

a single pattern, specifying character classes that should be preserved (see stringi-search-charclass). Defaults to `\P{Wspace}.

side

character [stri_trim only]; defaults to "both"

Value

All these functions return a character vector.

Details

Vectorized over str and pattern.

stri_trim is a wrapper, which calls stri_trim_left or stri_trim_right as appropriate. It's slightly slower than trim_left or trim_right, and so shouldn't be used except for convenience.

Contrary to many other string processing libraries, our trimming functions are quite general. A character class, given by pattern, may be adjusted to suit your needs (most often you will use the default value). On the other hand, for replacing pattern matches with arbitrary replacement string, see stri_replace.

Interestingly, with these functions you may sometimes extract data, which in some cases require using regular expressions. E.g. you may get "23.5" out of "total of 23.5 bitcoins".

For trimming whitespaces, please note the difference between Unicode binary property `\p{Wspace}` (more general) and general character category `\p{Z}`, see stringi-search-charclass.

Examples

Run this code

# NOT RUN {
stri_trim_left("               aaa")
stri_trim_right("rexamine.com/", "\\p{P}")
stri_trim_both(" Total of 23.5 bitcoins. ", "\\p{N}")
stri_trim_both(" Total of 23.5 bitcoins. ", "\\p{L}")

# }

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