R/search_count_4.R

In stringi: Fast and Portable Character String Processing Facilities

# kate: default-dictionary en_US

## This file is part of the 'stringi' package for R.
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#' @title
#' Count the Number of Pattern Occurrences
#'
#' @description
#' These functions count the number of occurrences
#' of a pattern in a string.
#'
#' @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_count} is a convenience function.
#' It calls either \code{stri_count_regex},
#' \code{stri_count_fixed}, \code{stri_count_coll},
#' or \code{stri_count_charclass}, depending on the argument used.
#'
#' @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 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 All the functions return an integer vector.
#'
#' @examples
#' s <- 'Lorem ipsum dolor sit amet, consectetur adipisicing elit.'
#' stri_count(s, fixed='dolor')
#' stri_count(s, regex='\\p{L}+')
#'
#' stri_count_fixed(s, ' ')
#' stri_count_fixed(s, 'o')
#' stri_count_fixed(s, 'it')
#' stri_count_fixed(s, letters)
#' stri_count_fixed('babab', 'b')
#' stri_count_fixed(c('stringi', '123'), 'string')
#'
#' stri_count_charclass(c('stRRRingi', 'STrrrINGI', '123'),
#'    c('\\p{Ll}', '\\p{Lu}', '\\p{Zs}'))
#' stri_count_charclass(' \t\n', '\\p{WHITE_SPACE}') # white space - binary property
#' stri_count_charclass(' \t\n', '\\p{Z}') # white-space - general category (note the difference)
#'
#' stri_count_regex(s, '(s|el)it')
#' stri_count_regex(s, 'i.i')
#' stri_count_regex(s, '.it')
#' stri_count_regex('bab baab baaab', c('b.*?b', 'b.b'))
#' stri_count_regex(c('stringi', '123'), '^(s|1)')
#'
#' @family search_count
#' @export
#' @rdname stri_count
stri_count <- 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 either `regex`, `fixed`, `coll`, or `charclass`")

    if (providedarg["regex"])
        stri_count_regex(str, regex, ...)
    else if (providedarg["fixed"])
        stri_count_fixed(str, fixed, ...)
    else if (providedarg["coll"])
        stri_count_coll(str, coll, ...)
    else if (providedarg["charclass"])
        stri_count_charclass(str, charclass, ...)
}


#' @export
#' @rdname stri_count
stri_count_charclass <- function(str, pattern) {
    .Call(C_stri_count_charclass, str, pattern)
}


#' @export
#' @rdname stri_count
stri_count_coll <- function(str, pattern, ..., opts_collator = NULL)
{
    if (!missing(...))
        opts_collator <- do.call(stri_opts_collator, as.list(c(opts_collator, ...)))
    .Call(C_stri_count_coll, str, pattern, opts_collator)
}


#' @export
#' @rdname stri_count
stri_count_fixed <- function(str, pattern, ..., opts_fixed = NULL)
{
    if (!missing(...))
        opts_fixed <- do.call(stri_opts_fixed, as.list(c(opts_fixed, ...)))
    .Call(C_stri_count_fixed, str, pattern, opts_fixed)
}


#' @export
#' @rdname stri_count
stri_count_regex <- function(str, pattern, ..., opts_regex = NULL)
{
    if (!missing(...))
        opts_regex <- do.call(stri_opts_regex, as.list(c(opts_regex, ...)))
    .Call(C_stri_count_regex, str, pattern, opts_regex)
}