R/search_detect_4.R

In stringi: Fast and Portable Character String Processing Facilities

# kate: default-dictionary en_US

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#' @title
#' Detect Pattern Occurrences
#'
#' @description
#' These functions determine, for each string in \code{str},
#' if there is at least one match to a corresponding \code{pattern}.
#'
#' @details
#' Vectorized over \code{str} and \code{pattern} (with recycling
#' of the elements in the shorter vector if necessary). This allows to,
#' for instance, search for one pattern in each given string,
#' search for each pattern in one given string,
#' and search for the i-th pattern within the i-th string.
#'
#' If \code{pattern} is empty, then the result is \code{NA}
#' and a warning is generated.
#'
#' \code{stri_detect} is a convenience function.
#' It calls either \code{stri_detect_regex},
#' \code{stri_detect_fixed}, \code{stri_detect_coll},
#' or \code{stri_detect_charclass}, depending on the argument used.
#'
#' See also \code{\link{stri_startswith}} and \code{\link{stri_endswith}}
#' for testing whether a string starts or ends with a match to a given pattern.
#' Moreover, see \code{\link{stri_subset}} for a character vector subsetting.
#'
#' If \code{max_count} is negative, then all stings are examined.
#' Otherwise, searching terminates
#' once \code{max_count} matches (or, if \code{negate} is \code{TRUE},
#' no-matches) are detected. The uninspected cases are marked
#' as missing in the return vector. Be aware that, unless \code{pattern} is a
#' singleton, the elements in \code{str} might be inspected in a
#' non-consecutive order.
#'
#'
#' @param str character vector; strings to search in
#' @param pattern,regex,fixed,coll,charclass character vector;
#'     search patterns; for more details refer to \link{stringi-search}
#' @param negate single logical value; whether a no-match to a pattern
#'     is rather of interest
#' @param max_count single integer; allows to stop searching once a given
#'    number of occurrences is detected; \code{-1} (the default) inspects all
#'    elements
#' @param opts_collator,opts_fixed,opts_regex a named list used to tune up
#'    the search engine's settings; see
#'    \code{\link{stri_opts_collator}}, \code{\link{stri_opts_fixed}},
#'    and \code{\link{stri_opts_regex}}, respectively; \code{NULL}
#'    for the defaults
#' @param ... supplementary arguments passed to the underlying functions,
#' including additional settings for \code{opts_collator}, \code{opts_regex},
#' \code{opts_fixed}, and so on
#'
#' @return Each function returns a logical vector.
#'
#' @examples
#' stri_detect_fixed(c('stringi R', 'R STRINGI', '123'), c('i', 'R', '0'))
#' stri_detect_fixed(c('stringi R', 'R STRINGI', '123'), 'R')
#'
#' stri_detect_charclass(c('stRRRingi','R STRINGI', '123'),
#'    c('\\p{Ll}', '\\p{Lu}', '\\p{Zs}'))
#'
#' stri_detect_regex(c('stringi R', 'R STRINGI', '123'), 'R.')
#' stri_detect_regex(c('stringi R', 'R STRINGI', '123'), '[[:alpha:]]*?')
#' stri_detect_regex(c('stringi R', 'R STRINGI', '123'), '[a-zC1]')
#' stri_detect_regex(c('stringi R', 'R STRINGI', '123'), '( R|RE)')
#' stri_detect_regex('stringi', 'STRING.', case_insensitive=TRUE)
#'
#' stri_detect_regex(c('abc', 'def', '123', 'ghi', '456', '789', 'jkl'),
#'    '^[0-9]+$', max_count=1)
#' stri_detect_regex(c('abc', 'def', '123', 'ghi', '456', '789', 'jkl'),
#'    '^[0-9]+$', max_count=2)
#' stri_detect_regex(c('abc', 'def', '123', 'ghi', '456', '789', 'jkl'),
#'    '^[0-9]+$', negate=TRUE, max_count=3)
#'
#' @family search_detect
#' @export
#' @rdname stri_detect
stri_detect <- function(str, ..., regex, fixed, coll, charclass)
{
    providedarg <- c(
        regex = !missing(regex),
        fixed = !missing(fixed),
        coll = !missing(coll),
        charclass = !missing(charclass))

    if (sum(providedarg) != 1)
        stop("you have to specify one of: `regex`, `fixed`, `coll`, or `charclass`")

    if (providedarg["regex"])
        stri_detect_regex(str, regex, ...) else if (providedarg["fixed"])
        stri_detect_fixed(str, fixed, ...) else if (providedarg["coll"])
        stri_detect_coll(str, coll, ...) else if (providedarg["charclass"])
        stri_detect_charclass(str, charclass, ...)
}


#' @export
#' @rdname stri_detect
stri_detect_fixed <- function(
    str, pattern, negate=FALSE, max_count=-1, ...,
    opts_fixed=NULL
) {
    if (!missing(...))
        opts_fixed <- do.call(stri_opts_fixed, as.list(c(opts_fixed, ...)))
    .Call(C_stri_detect_fixed, str, pattern, negate, max_count, opts_fixed)
}


#' @export
#' @rdname stri_detect
stri_detect_charclass <- function(str, pattern, negate = FALSE, max_count = -1)
{
    .Call(C_stri_detect_charclass, str, pattern, negate, max_count)
}


#' @export
#' @rdname stri_detect
stri_detect_coll <- function(
    str, pattern, negate = FALSE,
    max_count = -1, ..., opts_collator = NULL
) {
    if (!missing(...))
        opts_collator <- do.call(stri_opts_collator, as.list(c(opts_collator, ...)))
    .Call(C_stri_detect_coll, str, pattern, negate, max_count, opts_collator)
}


#' @export
#' @rdname stri_detect
stri_detect_regex <- function(
    str, pattern, negate = FALSE,
    max_count = -1, ...,
    opts_regex = NULL
) {
    if (!missing(...))
        opts_regex <- do.call(stri_opts_regex, as.list(c(opts_regex, ...)))
    .Call(C_stri_detect_regex, str, pattern, negate, max_count, opts_regex)
}