R/detect.R

In re2r: RE2 Regular Expression

## This file is part of the 're2r' package for R.
## Copyright (C) 2016, Qin Wenfeng
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#' Test a pattern in strings, and return boolean.
#'
#' Test a pattern in strings, and return boolean. Vectorised over strings and patterns.
#' @inheritParams re2_count
#' @examples
#' re2_detect("one", "(o.e)")
#' re2_detect("123-234-2222", "\\d\\d\\d-\\d\\d\\d-\\d\\d\\d\\d")
#'
#' words = c("sunny","beach","happy","really")
#' re2_detect(words, "y")
#' re2_detect(words, "^b")
#' re2_detect(words, "[abc]")
#'
#' # vectorize
#' (res = re2_detect("This", letters))
#' letters[res]
#'
#' letters[re2_detect("This", letters, case_sensitive = FALSE)]
#'
#' letters[re2_detect("This", re2(letters, case_sensitive = FALSE))]
#'
#' # In stringi, "" empty search patterns return NA.
#' # In re2r, empty search patterns will match
#' # empty string.
#'
#' re2_detect("abc", "")
#' stringi::stri_detect("abc", regex = "")
#'
#' @return A logical vector.
#' @export
re2_detect = function(string,
                      pattern,
                      anchor = UNANCHORED,
                      parallel = FALSE,
                      grain_size = 100000,
                      ...) {
    if (is.character(pattern) || mode(pattern) == "logical") {
        pattern = re2(pattern, ...)
    }
    cpp_match(stri_enc_toutf8(string),
              regexp = pattern,
              value = FALSE,
              anchor = anchor,
              all = FALSE,
              parallel = parallel,
              grain_size = grain_size)
}