trunc_at {mclm}

Truncate a sequence of character data

Description

This method takes as its argument x an object that represents a sequence of character data, such as an object of class tokens, and truncates it at the position where a match for the argument pattern is found. Currently it is only implemented for tokens objects.

Usage

trunc_at(x, pattern, ...)

## S3 method for class 'tokens'
trunc_at(
  x,
  pattern,
  keep_this = FALSE,
  last_match = FALSE,
  from_end = FALSE,
  ...
)

Arguments

x

An object that represents a sequence of character data.

pattern

A regular expression.

...

Additional arguments.

keep_this

Logical. Whether the matching token itself should be kept. If TRUE, the truncating happens right after the matching token; if FALSE, right before.

last_match

Logical. In case there are several matching tokens, if last_match is TRUE, the last match will be used as truncating point; otherwise, the first match will.

from_end

Logical. If FALSE, the match starts from the first token progressing forward; if TRUE, it starts from the last token progressing backward.

If from_end is FALSE, the part of x that is kept after truncation is the head of x. If it is TRUE instead, the part that is kept after truncation is the tail of x.

Value

A truncated version of x.

Examples

(toks <- tokenize('This is a first sentence . This is a second sentence .',
re_token_splitter = '\\s+'))

trunc_at(toks, re("[.]"))

trunc_at(toks, re("[.]"), last_match = TRUE)

trunc_at(toks, re("[.]"), last_match = TRUE, from_end = TRUE)