R/search_replace_4.R

In stringi: Fast and Portable Character String Processing Facilities

# kate: default-dictionary en_US

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#' @title
#' Replace Pattern Occurrences
#'
#' @description
#' These functions replace, with the given replacement string, every/first/last
#' substring of the input that matches the specified \code{pattern}.
#'
#' @details
#' By default, all the functions are vectorized over
#' \code{str}, \code{pattern}, \code{replacement} (with recycling
#' of the elements in the shorter vector if necessary).
#' Input that is not part of any match is left unchanged;
#' each match is replaced in the result by the replacement string.
#'
#' However, for \code{stri_replace_all*}, if \code{vectorize_all} is \code{FALSE},
#' then each substring matching any of the supplied \code{pattern}s
#' is replaced by a corresponding \code{replacement} string.
#' In such a case, the vectorization is over \code{str},
#' and - independently - over \code{pattern} and \code{replacement}.
#' In other words, this is equivalent to something like
#' \code{for (i in 1:npatterns) str <- stri_replace_all(str, pattern[i], replacement[i]}.
#' Note that you must set \code{length(pattern) >= length(replacement)}.
#'
#' In case of \code{stri_replace_*_regex},
#' the replacement string may contain references to capture groups
#' (in round parentheses).
#' References are of the form \code{$n}, where \code{n} is the number
#' of the capture group (\code{$1} denotes the first group).
#' For the literal \code{$},
#' escape it with a backslash.
#' Moreover, \code{${name}} are used for named capture groups.
#'
#' Note that \code{stri_replace_last_regex} searches from start to end,
#' but skips overlapping matches, see the example below.
#'
#' \code{stri_replace}, \code{stri_replace_all}, \code{stri_replace_first},
#' and \code{stri_replace_last} are convenience functions; they just call
#' \code{stri_replace_*_*} variants, depending on the arguments used.
#'
#' If you wish to remove white-spaces from the start or end
#' of a string, see \code{\link{stri_trim}}.
#'
#' @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 replacement character vector with replacements for matched patterns
#' @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 merge single logical value;
#' should consecutive matches be merged into one string;
#' \code{stri_replace_all_charclass} only
#' @param vectorize_all single logical value;
#' should each occurrence of a pattern in every string
#' be replaced by a corresponding replacement string?;
#' \code{stri_replace_all_*} only
#' @param vectorise_all alias of \code{vectorize_all}
#' @param mode single string;
#' one of: \code{'first'} (the default), \code{'all'}, \code{'last'}
#' @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 a character vector.
#'
#' @examples
#' stri_replace_all_charclass('aaaa', '[a]', 'b', merge=c(TRUE, FALSE))
#'
#' stri_replace_all_charclass('a\nb\tc   d', '\\p{WHITE_SPACE}', ' ')
#' stri_replace_all_charclass('a\nb\tc   d', '\\p{WHITE_SPACE}', ' ', merge=TRUE)
#'
#' s <- 'Lorem ipsum dolor sit amet, consectetur adipisicing elit.'
#' stri_replace_all_fixed(s, ' ', '#')
#' stri_replace_all_fixed(s, 'o', '0')
#'
#' stri_replace_all_fixed(c('1', 'NULL', '3'), 'NULL', NA)
#'
#' stri_replace_all_regex(s, ' .*? ', '#')
#' stri_replace_all_regex(s, '(el|s)it', '1234')
#' stri_replace_all_regex('abaca', 'a', c('!', '*'))
#' stri_replace_all_regex('123|456|789', '(\\p{N}).(\\p{N})', '$2-$1')
#' stri_replace_all_regex(c('stringi R', 'REXAMINE', '123'), '( R|R.)', ' r ')
#'
#' # named capture groups are available since ICU 55
#' \dontrun{
#' stri_replace_all_regex('words 123 and numbers 456',
#'    '(?<numbers>[0-9]+)', '!${numbers}!')
#' }
#'
#' # Compare the results:
#' stri_replace_all_fixed('The quick brown fox jumped over the lazy dog.',
#'      c('quick', 'brown', 'fox'), c('slow',  'black', 'bear'), vectorize_all=TRUE)
#' stri_replace_all_fixed('The quick brown fox jumped over the lazy dog.',
#'      c('quick', 'brown', 'fox'), c('slow',  'black', 'bear'), vectorize_all=FALSE)
#'
#' # Compare the results:
#' stri_replace_all_fixed('The quicker brown fox jumped over the lazy dog.',
#'      c('quick', 'brown', 'fox'), c('slow',  'black', 'bear'), vectorize_all=FALSE)
#' stri_replace_all_regex('The quicker brown fox jumped over the lazy dog.',
#'      '\\b'%s+%c('quick', 'brown', 'fox')%s+%'\\b', c('slow',  'black', 'bear'), vectorize_all=FALSE)
#'
#' # Searching for the last occurrence:
#' # Note the difference - regex searches left to right, with no overlaps.
#' stri_replace_last_fixed("agAGA", "aga", "*", case_insensitive=TRUE)
#' stri_replace_last_regex("agAGA", "aga", "*", case_insensitive=TRUE)
#'
#' @family search_replace
#' @export
#' @rdname stri_replace
stri_replace_all <- function(str, replacement, ..., 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_replace_all_regex(str, regex, replacement, ...)
    else if (providedarg["fixed"])
        stri_replace_all_fixed(str, fixed, replacement, ...)
    else if (providedarg["coll"])
        stri_replace_all_coll(str, coll, replacement, ...)
    else if (providedarg["charclass"])
        stri_replace_all_charclass(str, charclass, replacement, ...)
}


#' @export
#' @rdname stri_replace
stri_replace_first <- function(str, replacement, ..., 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_replace_first_regex(str, regex, replacement, ...)
    else if (providedarg["fixed"])
        stri_replace_first_fixed(str, fixed, replacement, ...)
    else if (providedarg["coll"])
        stri_replace_first_coll(str, coll, replacement, ...)
    else if (providedarg["charclass"])
        stri_replace_first_charclass(str, charclass, replacement, ...)
}


#' @export
#' @rdname stri_replace
stri_replace_last <- function(str, replacement, ..., 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_replace_last_regex(str, regex, replacement, ...)
    else if (providedarg["fixed"])
        stri_replace_last_fixed(str, fixed, replacement, ...)
    else if (providedarg["coll"])
        stri_replace_last_coll(str, coll, replacement, ...)
    else if (providedarg["charclass"])
        stri_replace_last_charclass(str, charclass, replacement, ...)
}


#' @export
#' @rdname stri_replace
stri_replace <- function(str, replacement, ..., regex, fixed, coll, charclass,
    mode = c("first", "all", "last"))
{
    # `first` is default for compatibility with stringr
    mode <- match.arg(mode)  # this is slow

    switch(mode,
        first = stri_replace_first(str, replacement, ..., regex = regex,
            fixed = fixed, coll = coll, charclass = charclass),
        last = stri_replace_last(str, replacement, ..., regex = regex,
            fixed = fixed, coll = coll, charclass = charclass),
        all = stri_replace_all(str, replacement, ..., regex = regex,
            fixed = fixed, coll = coll, charclass = charclass))
}


#' @export
#' @rdname stri_replace
stri_replace_all_charclass <- function(str, pattern, replacement, merge = FALSE,
    vectorize_all = TRUE, vectorise_all = vectorize_all)
{
    if (!missing(vectorise_all))
        vectorize_all <- vectorise_all

    .Call(C_stri_replace_all_charclass, str, pattern, replacement, merge, vectorize_all)
}


#' @export
#' @rdname stri_replace
stri_replace_first_charclass <- function(str, pattern, replacement)
{
    .Call(C_stri_replace_first_charclass, str, pattern, replacement)
}


#' @export
#' @rdname stri_replace
stri_replace_last_charclass <- function(str, pattern, replacement)
{
    .Call(C_stri_replace_last_charclass, str, pattern, replacement)
}


#' @export
#' @rdname stri_replace
stri_replace_all_coll <- function(str, pattern, replacement,
    vectorize_all = TRUE, vectorise_all = vectorize_all, ..., opts_collator = NULL)
{
    if (!missing(vectorise_all))
        vectorize_all <- vectorise_all
    if (!missing(...))
        opts_collator <- do.call(stri_opts_collator, as.list(c(opts_collator, ...)))
    .Call(C_stri_replace_all_coll, str, pattern, replacement, vectorize_all, opts_collator)
}


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


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


#' @export
#' @rdname stri_replace
stri_replace_all_fixed <- function(str, pattern, replacement,
    vectorize_all = TRUE, vectorise_all = vectorize_all, ..., opts_fixed = NULL)
{
    if (!missing(vectorise_all))
        vectorize_all <- vectorise_all
    if (!missing(...))
        opts_fixed <- do.call(stri_opts_fixed, as.list(c(opts_fixed, ...)))
    .Call(C_stri_replace_all_fixed, str, pattern, replacement, vectorize_all, opts_fixed)
}


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


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


#' @export
#' @rdname stri_replace
stri_replace_all_regex <- function(str, pattern, replacement,
    vectorize_all = TRUE, vectorise_all = vectorize_all, ..., opts_regex = NULL)
{
    if (!missing(vectorise_all))
        vectorize_all <- vectorise_all
    if (!missing(...))
        opts_regex <- do.call(stri_opts_regex, as.list(c(opts_regex, ...)))
    .Call(C_stri_replace_all_regex, str, pattern, replacement, vectorize_all, opts_regex)
}


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


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


#' Convert gsub-Style Replacement Strings
#'
#' @description
#' Converts a \code{\link[base]{gsub}}-style replacement strings
#' to those which can be used in \code{\link{stri_replace}}.
#' In particular, \code{$} becomes \code{\\$} and \code{\\1} becomes \code{$1}.
#'
#' @param x character vector
#'
#' @return Returns a character vector.
#'
#' @family search_replace
#' @export
stri_replace_rstr <- function(x)
{
    .Call(C_stri_replace_rstr, x)
}